is from scene two and is a sergeant's testimony of Macbeth's courage, loyalty, and his relentless pursuit of his king and country's enemies. The metaphors and similes create the impression of an honorable man who deserves respect.

...And with his former title greet Macbeth. 

Duncan makes this declaration at the end of scene two. He awards the title of the captured traitor, the thane of Cawdor, as a reward to Macbeth for his valour on the battlefield. This is significant because the witches later greet Macbeth with this title, also claiming that he would be 'king hereafter.'

All hail, Macbeth, hail to thee, thane of Cawdor!

All hail, Macbeth, thou shalt be king hereafter!

These greetings are extended by the second and third witches in scene 3. These are the predictions which spur Macbeth's ambitions. When he later discovers that the first prediction has come true, he believes that it is also his destiny to be king.

Thou shalt get kings, though thou be none:

This declaration, by the witches, is addressed to Banquo. It is important since it is this prophecy which mostly informs Macbeth's decision to have Banquo and his son, Fleance, murdered later. They are both seen as a threat not only to Macbeth but also to his lineage.

If chance will have me king, why, chance may crown me,Without my stir.

Macbeth utters these words in an aside after Ross had informed him about his being awarded the title, thane of Cawdor. He muses that if it should be his destiny to be king, that he might achieve the position without any action on his part. The quote indicates Macbeth's emphatic belief in the witches' predictions.

Glamis thou art, and Cawdor; and shalt beWhat thou art promised: yet do I fear thy nature;It is too full o' the milk of human kindnessTo catch the nearest way 

Lady Macbeth expresses her fear that her husband will not be ruthless enough to murder Duncan. She cannot wait for him to arrive so that she may encourage him.

...look like the innocent flower,But be the serpent under't. He that's comingMust be provided for:...

These are lady Macbeth's instructions in scene 5, after her husband's arrival. She tells him, by using an apt simile, to act in a convivial manner whilst plotting the king's assassination. He should not act in a suspicious manner, for Duncan must be taken care of, innuendo for the fact that he must be murdered. These lines indicate Lady Macbeth's perfidy. Ambition has made her ruthlessly determined to usurp the crown.

We will proceed no further in this business:

Told to lady Macbeth in scene 7. Macbeth has reconsidered his decision to murder his king but is soon persuaded by his wife to proceed. The line indicates that he still has integrity and also fears that they might fail in their pernicious venture. It also shows that, at this juncture, Lady Macbeth is much more heartless than her husband.

Act 2:

Is this a dagger which I see before me,
The handle toward my hand?

This quote in scene 1, indicates Macbeth's state of mind. He is completely overwhelmed by the evil which he is about to commit and hallucinates seeing a dagger leading him to Duncan's chamber. The entire monologue in this instance indicates Macbeth's terrible travesty. He is tortured by the thought of killing his king and believes that the images of death and destruction he sees are all false, created by the anxiety he is experiencing, which he calls 'a heat-oppressed brain.'

I'll go no more:I am afraid to think what I have done;Look on't again I dare not.

This quote indicates that Macbeth has not reconciled with the fact that he has committed such a terrible deed. He has brought the daggers with which he killed Duncan with him and Lady Macbeth has instructed him to return them. He cannot go back and witness the carnage again. he is filled with trepidation. Lady Macbeth then returns the instruments of murder herself and places them on Duncan's guards, implicating them.

A little water clears us of this deed:

This quote from Lady Macbeth is a euphemism and indicates the obvious difference between her and her husband's attitudes to the murder. She is almost flippant about it, whilst Macbeth is tortured and believes that he will never wash Duncan's blood off his hands, and it will, instead, taint all the oceans. He is overwhelmed by guilt.

Had I but died an hour before this chance,I had lived a blessed time; for, from this instant,There 's nothing serious in mortality:

Macbeth's facetious and dishonest remark in the form of a juxtaposition here, indicates his depravity. His purpose is clearly to deceive others to believe that he feels great sorrow at this most heinous crime. The dramatic irony is obvious.

O, yet I do repent me of my fury,That I did kill them.

Macbeth confesses that he has killed Duncan's two guards in a moment of passionate fury at their malice. He states that he had lost all reason in that instance. The true purpose, however, was to avoid all suspicion. The guards could have implicated him or his wife.

Malcolm and Donalbain, the king's two sons,Are stol'n away and fled; which puts upon themSuspicion of the deed.

Macduff expresses, in scene 4, the fact that Duncan's two sons have escaped, which creates the suspicion that they are responsible for their father's murder. In fact, they were in fear of their own lives and decided to leave, lest they also become victims of the evildoers' plot. 

Well, may you see things well done there: adieu!Lest our old robes sit easier than our new!

Macduff tells Ross, also in scene 4, quite sarcastically, that he is not going to Scone to witness Macbeth's coronation, but wishes him well in going there. His later remark reveals his suspicion of Macbeth for he expresses the sentiment that they may find that their erstwhile positions under king Duncan were better than they would now be under Macbeth's rule. He clearly also feels vulnerable and threatened. 

Your essay: 

Begin with a strong thesis statement in your opening paragraph in which you present the idea of how the occurrences in these two acts determined and affected the development of all the events in the play.

You can use the quotes to construct paragraphs which would relate the most pertinent occurrences in the two acts. The quotes also provide insight into the characters' mindsets during such events. Each paragraph can be constructed around one or two quotes. The quotes also provide a linear sequence of events which would accurately describe how Macbeth and his wife's plot developed.

Your conclusion can provide a brief summary regarding the fact that the Macbeths had achieved their pernicious purpose and some suggestion as to how things may develop further. Look especially for the irony in their actions.

The most compelling drama of Act One of Shakespeare's Macbeth is the allure of the witches in drawing the once honorable and highly respected Macbeth into a plot to kill Duncan—his King, his cousin and his friend.

In Act One, scene one, the witches set the mood for the play. In Shakespeare's time, the Elizabethan audiences very much believed in the supernatural—in witches, fairies and ghosts. Along with a belief in these beings, people also believed that the powers of evil worked hard to win honest souls to their eternal damnation. (This belief was carried over into American literature—the influences seen in works such as Young Goodman Brown by Nathaniel Hawthorne.) The presence of the witches would most certainly have made a strong impact on the viewer—just as a monster or murderer would in the opening scene of a movie and television show with today's audiences. It is noted that in Macbeth...

...ambition conspires with unholy forces to commit evil deeds...

In scene one, the witches announce that they will meet again, seeking out Macbeth. This element is essential to creating this compelling drama. As we learn more about Macbeth and his vaulting ambition (his need to be great), we realize that the play would never have worked had the witches met Banquo, who was also a loyal general for Duncan, but was stronger ethically and morally.

The witches also use language that sets the tone, referring to...

...the fog and filthy air. (12)

Besides the fact that a war is being waged, evil is in the air: it's not just foggy, it's "filthy," a word that is easily associated with the witches.

In scene two, Duncan is given a report of the valiant way Macbeth defeated the traitorous Macdonwald and widely praises him. There is no question of the depth of Duncan's respect for Macbeth, allowing that no one will suspect the monster Macbeth is to become.

In scene three, the witches prove themselves to be as diabolical as one might expect, describing the poor sailor they have tormented, and casting a spell.

Then Macbeth and Banquo appear as expected. Here the witches make their predictions, which (in themselves) are not dangerous; but Macbeth's immediate preoccupation is when the title "Thane of Cawdor" is given to him. Macbeth imagines that if the witches told the truth of Cawdor, he will also be king—even though it would mean Duncan would have to be dead.

Meeting the King in scene four, Duncan praises Macbeth, but also names his son Malcolm as his heir. Macbeth notes that this is an obstacle in his path, showing that he is already planning to make his way to the throne, one way or another. By scene five, we learn that Lady Macbeth will do anything to make sure her husband becomes King. She is also set on murder as she describes...

...the fatal entrance of Duncan (40)

Lady Macbeth also calls on evil forces:

Come, you spirits
That tend on mortal thoughts…
And fill me, from the crown to the toe, top-full
Of direst cruelty! (41-44)

By scene six, Duncan is staying at Macbeth's castle. Macbeth is unsure about the assassination, but Lady Macbeth is not. She swears that she has the mettle to kill her own child if it were necessary. Macbeth agrees to proceed: his path is set to commit regicide.

MACBETH:
I am settled, and bend up
Each corporal agent to this terrible feat. (90-91)

The compelling drama is the evil and death introduced by the witches—coupled with Macbeth's ambition—that will galvanize the play toward its tragic conclusion.

Act 1

Witches give predictions to Macbeth, Banquo demands predictions as well. Thane of Cawdor is found to be a traitor, Duncan (the king) gives his title to Macbeth (foreshadowing and the witches' prediction come true). Macbeth thinks of killing Duncan to become king, but instantly rejects the idea. Lady Macbeth receives a letter from Macbeth telling about the prophesies. She thinks of killing Duncan, who has decided to visit the Macbeth's castle, but fears Macbeth will be too weak to do it. She convinces Macbeth that he must kill Duncan.

Act 2

Banquo questions Macbeth who claims he has given no thought to the prophesies, then he imagines a bloody dagger floating in the air which leads him to Duncan's chamber. Lady Macbeth has already drugged the guards and gotten them drunk. After Macbeth kills Duncan (off stage) he returns with a bloody dagger in hand, Lady Macbeth returns it to the guards and covers them with blood to make it look like they killed Duncan. There is a knocking at the door which leads to the comic relief (tension breaker) Porter scene; the drunken porter pretends to be opening the gates at Hell. Macduff and   to wake Duncan, Macduff discovers the king murdered. Macbeth, in an apparent fit of rage kills the guards. Duncan's sons Malcolm and Donalbain decide they may not be safe so flee to England and Ireland. A few days later Ross and an old man discuss the supernatural happenings when MacDuff arrives to report the suspicions against Macbeth (for killing the guards) and Ducnan's two sons (for fleeing), but notes that Macbeth will become king. Ross goes to Scone for the coronation but MacDuff instead heads home (hinting at his distrust of Macbeth, and foreshadowing future conflict).

There are many significant actions that take place during Acts one and two in Macbeth by Shakespeare. 

The first significant act is when the witches approach Macbeth and Banquo to tell them their future. They tell them that Macbeth will become Thane of Cawdor and finally king. They then tell Banquo that he will never be king but his descendants will be. This action is significant because it is the catalyst that creates Lady Macbeth and Macbeth's power hungry actions as the story progresses. Whether or not their prophecy is truth or self-fulfilling isn't important, what is important is that it causes Macbeth's downfall.

The next significant act is Lady Macbeth persuading Macbeth into killing King Duncan when he comes to visit their home. Lady Macbeth succeeds in convincing and planning, and the murder is committed at the beginning of Act 2.

The murder is of course a significant action because it turns the kingdom upside down as Macbeth has violated the great chain of being. He kills the king who is a direct link to God according to the culture of  the time. This act throws of the human world as well as the natural world. Duncan's death causes Donalbein and Malcolm to be fearful, and Malcolm says "Where we are, / There’s daggers in men’s smiles; the nea’er in blood, / The nearer bloody.”" The two sons of Duncan flee to other countries. This act allows Macbeth to call their quick departure guilt and take the crown. 

Macbeth's words "So foul and fair a day I have not seen" express both the bellicose and bizarre happenings of the day as well as the unpropitious and victorious occurrences of Act I of Shakespeare's play Macbeth. 

Ostensibly a foul day, Macbeth later emerges from a bloody battle with the traitorous Macdonwald as the "fair" victor and is named Thane of Cawdor. After this, he enters a heath and sees the "weird sisters," who are menacing, and who seem to blur the lines between good and bad, making "nothing what is not"—that is, both "fair" and "foul." Then, they predict that he will become king. And, although these new honors seem wonderful, they do not sit well with Macbeth and he wants to think more about them.

Later in Scene 5, Lady Macbeth changes the good news of Macbeth's elevation to Thane of Cawdor to concern about Macbeth's becoming king and his lack of desire to go after the crown. Further, she urges him to kill King Duncan while he is at their castle. This urging of hers puts Macbeth into a brown study and he becomes lost in the dark thoughts of his "vaulting ambition" in a soliloquy in which he vacillates between "fair" and "foul" thoughts on the goodness of Duncan who is a kinsman and a king who has been blameless in his office in contrast to Macbeth's own "vaulting ambition which o'erleaps itself."

Finally, in the last scene after he has committed "this terrible feat" of regicide, Macbeth becomes more foul as he vows that "False face must hide what the false heart doth know" so that the "foul" acts of his will seem "fair."

Act I, scene i of William Shakespeare's Macbeth could be defined as one of the most intense of the entire play. This scene sets the mood of the play as a whole. The opening image of the witches chanting during an intense thunderstorm show the play to be one which will be filled with dark imagery, supernatural elements, and evil (given the stereotypical thoughts about witches).

Given that the scene sets the mood for the rest of the play, the scene is very important. Without this scene, the play would look more like one of Shakespeare's history plays (like Julius Caesar and Henry V) given the second scene of act one shows a battlefield and dialogue consists of talk of battle and valor.

Although murder and plotting extends throughout the play, it is the initial scene which puts all other action into context. It is the witches quote, "Foul is fair, and fair is foul," which sets the paradoxical nature of the play in motion. Readers and viewers are cued into the fact that nothing will be as it seems throughout the play.

This scene is pivotal in the plot's development because this is when Macbeth truly takes hold of the ambitious desires which will lead him to commit several murders in order to claim what he believes is rightfully his.

The witches appear and cast some predictions for Macbeth. They tell him that he will be Thane of Cawdor and king in the future, and at first he questions how this could possibly be true. After all,

The thane of Cawdor lives,
A prosperous gentleman, and to be king
Stands not within the prospect of belief,
No more than to be Cawdor. (1.3.76–79)

Yet later in this scene, when Angus tells Macbeth that the current Thane of Cawdor is "under heavy judgement" and deserves death, he also tells Macbeth that he's gained a new title: Thane of Cawdor.

This brings truth to one of the witches' predictions, and Macbeth has a choice to make here. He could proceed with caution or count it as an odd coincidence that one of the predictions of these odd witches has come to fruition. But he doesn't choose that path.

Instead, Macbeth latches on to the promise that he will be king as a certainty:

Two truths are told,
As happy prologues to the swelling act
Of the imperial theme. (1.3.140–142)

This begins to shape all of Macbeth's thoughts, and he turns almost immediately to murderous thoughts and realizes that his "present fears / Are less than horrible imaginings" (1.3.151–152).

In this scene, Macbeth also states that

If chance will have me king, why, chance may
crown me
Without my stir. (1.3.158–160)

Yet once the thought is planted that he could rise to become King, he "stirs" fate quite a bit, not content to allow "chance" to decide whether he should actually be king.

Macbeth's true character begins to come to light in this scene—and it's one who's willing to take the prophecies of three witches seriously enough that he believes it is his rightful destiny to claim their predictions as his truth, at any cost to those who stand in his way.

Equally significant is the introduction in "Macbeth" of the supernatural element to this play which is pivotal to the tragic downfall of Macbeth who goes from being lauded as a brave and fearless warrior--"O valiant cousin!  Worthy gentleman!" as King Duncan calls him--to a loathed murderer--"Thou bloodier villain" as Macduff addresses him.

The belief in the prophecies of the witches that Macbeth hears is what impels him to his ambitions of power.  He considers that he may not have to do anything to become king:

If chance will have me King, why,chance may crown me/Without my stir (I,iii,44-45)

This interest in the supernatural world captivates not only Macbeth, but the Elizabethan audiences as well who revel in such lines as "nothing is /But what is not" (I,iii,142).  Indeed, themes of evil spirits and witchcraft were very popular in these times.  When Macbeth returns later in the play to speak with the three "weird sisters" he is so disturbed by their next prophesies that he initiates his murderous actions to prevent his own demise.  Of course, tragically he has been entrapped by this preternatural world of the witches.

Act I, Scene iii is the first appearance of the “weird sisters,” called the Witches.  Banquo and Macbeth encounter them in the woods. The Witches address Macbeth as “Thane of Cawdor” and “King,” confusing the two soldiers because those two nobles are still alive and holding their titles. Banquo asks if the sisters have a prophecy for him as well. They predict that he will be “lesser” than Macbeth and “greater,” and that his sons will be kings though he himself will not. After the Witches disappear, two more soldiers greet Banquo and Macbeth and inform them that the king has named Macbeth Thane of Cawdor.

This scene sets the stage for the rest of the plot, that Macbeth will launch a quest for power and stop at nothing short of murder to achieve his ambitions.

Act 1, scene 4, of William Shakespeare's Macbeth begins with Malcolm telling his father, King Duncan, that the Thane of Cawdor confessed his treason for betraying his allegiance to Duncan and died a dignified, if not entirely honorable, death.

MALCOLM. Nothing in his life
Became him like the leaving it... (1.4.8–9)

Duncan responds with one of the many portentous remarks that he and others will utter in this scene.

DUNCAN. There's no art
To find the mind's construction in the face... (1.4.13–14)

Duncan seems to be reprimanding himself for not being a very good judge of the Thane of Cawdor's character. Macbeth, who is significantly more treacherous than he appears, makes a timely entrance just as Duncan finishes this line.

In the scene just before this one, the audience heard one of the witches prophesy that Macbeth would be king, and they heard Macbeth's unsettling reaction:

MACBETH. [W]hy do I yield to that suggestion
Whose horrid image doth unfix my hair
And make my seated heart knock at my ribs,
Against the use of nature? (1.3.145–148)

The prophecy aroused frightening ambitions in Macbeth about being king (which he had apparently already considered), but he's not yet sure how he's going to achieve that goal.

Duncan praises Macbeth for his victories in battle and says that he regrets that he couldn't reward Macbeth with more than just the Thane of Cawdor's title and property.

Macbeth then oversells his loyalty to Duncan—compensating for the treachery in his heart—and Duncan responds by embracing Macbeth and telling him that he's setting the stage for bigger and better things for him.

DUNCAN. Welcome hither.
I have begun to plant thee, and will labor
To make thee full of growing. (1.4.31–33)

Little does Duncan realize that the seeds of Macbeth's ambitions are already growing and will come to fruition in a very short time.

Duncan likewise embraces Banquo and tells him that he is no less deserving of praise than Macbeth. Banquo responds with a reference to Duncan's words to Macbeth.

BANQUO. There if I grow,
The harvest is your own. (1.4.37–38)

In essence, what Banquo is unknowingly and ironically saying to Duncan is, "as you sow, so shall you reap." This has a much more significant meaning with regard to Macbeth than to Banquo, who, along with Duncan, will cease to "grow" in a very short time.

Duncan announces to his sons, generals, and thanes that he has chosen his son Malcolm to succeed him as king.

This announcement somewhat thwarts Macbeth's ambitions, but he doesn't seem to be particularly concerned about it.

MACBETH. That is a step
On which I must fall down, or else o'erleap,
For in my way it lies. (1.4.55–57)

It's Malcolm who should be concerned. Macbeth considers overleaping Malcolm as simply another step along the way to fulfilling his ambition to become king.

MACBETH. Stars, hide your fires;
Let not light see my black and deep desires:
The eye wink at the hand; yet let that be
Which the eye fears, when it is done, to see. (1.4.57–60)

Macbeth exits the scene, leaving his thoughts with the audience, who are left to wonder whether Macbeth will actually pursue his ambitions, and, if so, how he'll go about it.

Duncan and Banquo have been talking off to the side while Shakespeare had Macbeth think out loud for the audience. Duncan has a few more portentous remarks to make.

DUNCAN. True, worthy Banquo! He is full so valiant,
And in his commendations I am fed;
It is a banquet to me. Let's after him,
Whose care is gone before to bid us welcome:
It is a peerless kinsman. (1.4.61–65)

Duncan is completely misled by the extravagant promises of duty and loyalty that Macbeth "fed" him earlier in the scene.

The mention of "a banquet" foreshadows the banquet which the ghost of Banquo will attend, to Macbeth's dismay.

Macbeth has gone ahead to prepare Duncan's "welcome," but Duncan has no idea that it will be the last welcome he ever gets from anyone on this earth.

Finally, Macbeth truly is a "peerless kinsman," unrivaled and unequaled in what will be shown to be his murderous ambition.

 Act 1, Scene 4 is important for three reasons. Firstly, King Duncan announces that his eldest son, Malcolm, will become the king of Cumberland, which means that he is now next in line to the throne. This means that Macbeth now faces more opposition if he is to stick with his plot of becoming the King of Scotland.

Secondly, this scene foreshadows the tragic events yet to come in the play. Macbeth begins to become a tragic hero from this scene onwards. This is because we learn that despite King Duncan's desire to reward Macbeth for his bravery and loyalty, which means Macbeth can develop and thrive as a warrior and as a man, Macbeth wants to be the king and will do anything to achieve that. He proclaims that he will have to get rid of Malcolm because he stands in his way of becoming the king:

 The Prince of Cumberland! that is a step
 On which I must fall down, or else o'erleap,
For in my way it lies.

Thirdly and lastly, this scene documents the gullibility of King Duncan because he trusts Macbeth just like he trusted the Thane of Cawdor, who turned out to be disloyal and treacherous.

This scene serves two main purposes:

1. to reinforce the basic good-heartedness of Duncan's nature, showing that there is no reason that he should not continue to rule as a wise and just King,
2. and to begin to build the suspense that leads up to the murder of Duncan.  To create this suspense, Shakespeare uses dramatic irony.

Duncan, immediately upon entering, says, "This castle hath a pleasant seat."  A double whammy of dramatic irony (In scene v, the audience has just heard Lady Macbeth say that Duncan "never shall" see the "morrow.") and support of the open-hearted way that Duncan is prepared to embrace Macbeth and his wife.

Banquo also adds to the irony when he says, "Heaven's breath/Smells wooingly here."  The irony here, of course, is that Heaven must be far from this place, as Lady Macbeth has just called upon "thick night" to "pall [her] in the dunnest smoke of Hell."

The balance of the scene is an interaction between Duncan and Lady Macbeth, which adds to the dramatic irony and suspense, but also reveals how very cunning and cool Lady Macbeth can be.  She doesn't bat an eye as she lies in the very face of the man heaping compliments upon her, knowing that she will be witness to his death before the next sun rises.

For more on this scene, please follow the links below.

In Macbeth, Macbeth, with much persuasion from Lady Macbeth, has resolved to murder Duncan. This has come about after Macbeth, returning victorious from battle, receives information from the three witches that not only will he be rewarded for his efforts by being made Thane of Cawdor but he will also be king. It seems that he and Lady Macbeth must plot to ensure their future, although Macbeth, at the beginning of Act II, is still deeply troubled by the events he anticipates will follow. 

The scene with the daggers (scene i), is most important because it speaks to Macbeth's state of mind. He is aware that the dagger is a vision. It encourages him with its "handle toward my hand" (34); it excites him, as he is eager to "clutch thee," and it overwhelms him as he suffers from "the heat-oppressed brain" (39). It also serves as a premonition because he sees the blood dripping from it and it also goads him to perform the wicked deed such as Tarquin, the tyrannical ruler, would have done. Lastly, it scares him but also strengthens his resolve as he says, "I go, and it is done; the bell invites me" (62).

In scene ii, Lady Macbeth's concerns for Macbeth reveals her resolve. She is still not convinced that Macbeth is capable and her remark that, "Had he not resembled My father as he slept, I had done't" (12), is significant in revealing a potential weakness in her otherwise unwavering disposition. The most important event is the actual murder and Macbeth's confusion; he believes that he "does murder sleep" (36). In this confusion he still has the daggers in his hand and Lady Macbeth has to step in and return them to Duncan's chamber and still convince Macbeth that "A little water clears us of this deed" (67), meaning that blood can be washed from their hands. Neither of them are prepared for the psychological torment and irrational decisions that will follow.

The most significant event in scene iv, is the meeting between Ross, the old man, and Macduff, when Macbeth's "sovereignty," in the absence of Donalbain and Malcolm, is discussed. The old man's comment, in the form of almost a blessing and a means to hopefully protect them, is important as it drives the plot of Macbeth when we have "good of bad, and friends of foes" (41). 

Several important events occur in Act II of Shakespeare’s Macbeth.

Scene 1: Banquo and Fleance have insomnia. Banquo tells Macbeth he dreamed about the evil witches and is worried, but Macbeth dismisses his worries. Macbeth has a vision of a dagger covered with blood. Macbeth enters Duncan’s room.

Scene 2: Lady Macbeth hears an owl. Macbeth returns to her, daggers in hand, after killing Duncan. Lady Macbeth places daggers near Duncan. They return to bed.

Scene 3: Porter greets Lennox and Macduff. Murder of Duncan is discovered.

Scene 4: Ross reports prodigies concerning Duncan’s horses, birds and weather. It’s announced that Macbeth will be king. Macduff leaves.

The dagger seeks to solidify the mental process Macbeth goes through from his meeting with the witches until his murder of Duncan.  The soliloquy serves the dramatic purpose both of explaining his thought process and demonstrating his mental instability.

In Act 1, Macbeth has already established his ambition.  Duncan tells him how pleased he is with his bravery, and rewards him with the promotion to the title of Thane of Cawdor.  Macbeth is not satisfied.  The witches have told him he will be king, so he expects Duncan to name him, not the king’s son, as his successor.

[Aside.] The Prince of Cumberland! That is a step(55)
On which I must fall down, or else o'erleap,
For in my way it lies. Stars, hide your fires;
Let not light see my black and deep desires:
The eye wink at the hand; yet let that be
Which the eye fears, when it is done, to see.(60) (Act 1, Scene 5, enotes etext pdf p. 18)

Things get further complicated because Macbeth has written home to his wife and told her what the witches said.  LadyMacbeth’s attitude is that if Duncan won’t give Macbeth what he deserves, Macbeth should just take it!

Macbeth, while ambitious, was apparently not overly so until the witches and Lady Macbeth encouraged him.  His wife tells him to pretend to be nice to Duncan and then take him out.

To beguile the time,
Look like the time; bear welcome in your eye,
Your hand, your tongue; look like the innocent flower,(70)
But be the serpent under't. (Act 1, Scene 5, p. 20)

Macbeth tells her they’ll talk about it later.  She has stirred things up in him, and he cannot decide what to do.  He sort of feels like Duncan is his kinsman (they are related), and it would be wrong to kill him.

He's here in double trust:
First, as I am his kinsman and his subject,
Strong both against the deed; then, as his host (Act 1, Scene 7)

It is this guilt and confusion that leads Macbeth to imagine or hallucinate the floating dagger.  He has already decided, “I have no spur/To prick the sides of my intent, but only/Vaulting ambition, which o'erleaps itself/And falls on the other” (Act 1, Scene 7).  It is here that Lady Macbeth interrupts him.  He feels like Duncan has done nothing to deserve murder.  Lady Macbeth tells him “screw your courage to the sticking-place” (p. 24) and leaves him to ponder.

By Act 3, Scene 1, Macbeth sees the dagger.  He talks directly to it, wondering if it is real why he cannot touch it.

Or art thou but(45)
A dagger of the mind, a false creation,
Proceeding from the heat-oppressed brain? (Act 3, Scene 1)

He basically is asking himself, AM I CRAZY?  The audience might be wondering the same thing.  Yet, through the device of the dagger, they realize that he might be.  Yet by the end of the soliloquy, Macbeth has made up his mind to kill Duncan, and the audience is right there with him.  "Macbeth’s conscience creates the vision of the dagger, either to halt his plans by revealing the horror of the act or, as Macbeth believes, to beckon him forward." (enotes Act 2 summary and analysis)

Certainly Macbeth and Banquo's conversation about the "three weird sisters" serves multiple dramatic purposes:

1.  Their conversation brings up the prophecy concerning both Macbeth and Banquo's possible futures.  Their brief discussion reminds the audience and keeps the imagery of the witches fresh in their mind.

2.  Banquo and Macbeth's conversation further reveals Macbeth's ability to lie and deceive.  He tells Banquo that he has hardly thought of the witches' words, although the audience knows that is hardly the case!  Macbeth comes across in this scene as looking so genial and the very picture of a perfect host and friend, which of course, serves as a bold contrast to the end of the scene in which he contemplates murdering the king. 

In Shakespeare's Macbeth, the tragic hero, Macbeth, says this referring to Banquo and his son, Fleance.  Banquo is the serpent and Fleance is the worm.  Banquo lies dead (he's been killed by Macbeth's hired killers), but Fleance escaped and is still alive.  In time, Fleance will grow and, presumably, seek to avenge his father's murder by coming after Macbeth.  But in the play's present, Fleance is still a child. 

The idea is that Fleance, as a child, is no threat to Macbeth--at least not in terms of raising an army and attempting to seize the throne.  In the future he may be a physical threat, but not in the play's present.  Macbeth doesn't have to worry about him for now. 

Of course, in the bigger picture, Fleance's escape signals the doom of Macbeth's hope of creating a dynasty.  According to the witches' predictions, Banquo's heirs will rule.  Macbeth attempts to change his "fate" when he orders both Banquo and Fleance killed.  But he fails.

The opening scenes of many plays tend to serve the same purpose--to introduce characters, plot, setting, initial conflict and mood. This is no different with William Shakespeare's Macbeth. While the first two scenes are not being referred to in the question, the opening scene of the play sets the ominous and dark mood of the scenes to follow (developed through the use of the witches casting spells).

The scenes in question, three (3) through six (6), are significant given they set up Macbeth's path throughout the play. In scene three, Macbeth comes to find out that he will obtain the crown one day. This hope pushes Macbeth's already large ambitious nature, insuring that Macbeth will do whatever it takes to obtain the crown.

Scene four sets into motion the conflict which will arise between Macbeth and Malcolm (given Malcolm has been named to take the throne after his father's death).

Scene five is important because it shows Lady Macbeth to be as cold-hearted and as ambitious as her husband. Readers learn that Lady Macbeth will stop at nothing to have her husband king (even changing her own gender--given she does not believe her husband is "man enough" to do what needs to be done).

In the end, the scenes in question are significant given they establish better (deeper) understanding of the characters (especially Lady Macbeth and Macbeth), set up conflict, and show where the conflict stems from (the prophecies).

Act III, scene one begins with what is termed a soliloquy, which is when a character speaks his thoughts out loud for the audience to hear. Banquo has an opening soliloquy in which he expresses his belief that Macbeth murdered his way to the throne. He also, however, feels relatively safe because he clings to the witches' prophecy that his descendants will be kings.

After this, Macbeth, Lady Macbeth, and their entourage enter. Macbeth speaks to Banquo with exaggerated kindness, and Banquo is very deferential, showing how much the power dynamic between the two men has changed. They are no longer comrades in battle and equals, but monarch and subject.

Macbeth then meets with his murderers and lays out the plan he has already devised to murder Banquo. He is afraid of Banquo and what he knows:

Our fears in Banquo
Stick deep, and in his royalty of nature
Reigns that which would be feared.

The murderers are angry men willing to take out their aggression against anyone, and so the scene ends with the murder plot in hand.

Macbeth's revelation of the plan so that the audience knows it, but Banquo and the others, such as Lady Macbeth don't, is called dramatic irony.

This scene is significant because it shows Macbeth's conscience hardening and is another step on his road to tyranny. He is not completely hardened yet, but he is able to turn cold-bloodedly on an old friend (he will feel guilt later). What's also important is that Macbeth resents that his former friend's sons will be kings while Banquo has done none of the dirty work of actually being king. This bitterness suggests that being king is not what Macbeth expected when he dreamed of stepping into that role.

Dramatic irony is when the reader/audience knows something that the actor/character does not.  At this point in time, we know that Macbeth is behind the death of King Duncan.  Banquo at this point assumes the same thing. 

"Thou hast it now: king, Cawdor, Glamis, all,As the weird women promised, and, I fear,Thou play'dst most foully for't"

However, it is too late since Macbeth is planning on having him killed. We know this, but Banquo doesn't realize yet how evil Macbeth truly is. Macbeth asks many questions trying to find what Banquo's route will be.

"Ride you this afternoon?"

"Is't far you ride?"

When Macbeth tells him "Fail not our feast," Banquo replies that he won't miss it.  That could be considered foreshadowing since Banquo does appear, but he appears as a ghost.

Act III, Scene IV, is important because it is Macbeth's high point as King.  Once he sees the ghost, his image as king is changed, tarnished with questions of madness. 

"Then comes my fit again: I had else
been perfect;
Whole as the marble, founded as the rock,
As broad and general as the casing air:
But now I am cabin'd, cribb'd, confin'd, bound in
To saucy doubts and fears. But Banquo's safe?" (Act III, Scene IV)

"Can such things be
And overcome us likes a summer's cloud,
Without our special wonder? You make me
strange
Even to the disposition that I owe,
When now I think you can behold such sights,
And keep the natural ruby of your cheeks,
When mine are blanch'd with fear." (Act III, Scene IV)

Macbeth begins to question his sanity, he can't believe his eyes, yet he cannot look away from Banquo's ghost.  In front of his dinner guests, he acts in an unstable, irrational manner, causing Lady Macbeth to make excuses for his behavior.  At this point, King Macbeth has lost some of the respect and admiration of his court. 

His subjects do not look at him the same way after this scene, it is a turning point for Macbeth. His manner and attitude becomes more tyrannical, he decides after this scene to consult the witches again, to seek their guidance.

Macbeth begins the slow descent into madness after this scene, losing his ability to control the future, something that he has killed to achieve. 

Act III, Sc. iv (commonly known as the Banquet Scene) is important in two directions. Firstly it gives a clear picture of Macbeth’s psyche. Secondly it helps to create the supernatural atmosphere of Macbeth. When Macbeth speaks to the ghost of Banquo (who however cannot reply) the audience knows how deeply Macbeth has been suffering from the feeling of guilt. The scene also projects how Lady Macbeth continuously tries to help Macbeth in difficult situation. The eNotes commentary of this scene is an extremely useful resource and should be studied for a thorough understanding.

In Macbeth, Scene 4 of Act III is significant to the drama because it is the first time in the play that Macbeth voices his inner conflicts in public; this revelation of his fears to others marks a turning point in the play. For, events at the banquet show that Macbeth can no longer pretend to be innocent.   

Despite Lady Macbeth's attempts to explain to the guests that Macbeth's "fit is momentary" (III,iv,67), the guests are bewildered as Macbeth talks to the ghost of Banquo, challenging it, even.  Lady Macbeth has lost control of her husband, so she asks them to leave lest they hear him confess his murder of Duncan.

In addition to the revelation of Macbeth's fears, there is much mention of blood by Macbeth as well as the supernatural: 

It [the ghost] will have blood, they say:  blood will have blood./Sones have been known to move and trees to speak;/Augures and unerstood relations have/By maggo-pies and choughs and rooks brought forth/Te secret'st man of blood.  What is the night?

Macbeth feels himself mired in blood, murder, and at the mercy of the supernatural with the omens that he senses.  In short, he is very conflicted and disturbed.  This disturbance within Macbeth and the references to blood foreshadow both his bloody end and the breakdown of Lady Macbeth, as well.

The scene has a number of functions. First, it introduces a break from Macbeth and his woes. He has just seen Banquo's ghost and was terribly frightened, so much so that his wife had to admonish him for being "unmanned in folly" and for breaking up the banquet with his disorderly conduct.

Second, it provides a link between the first part of the play (in which Macbeth met with the witches) and what we shall soon find are the true consequences of that initial meeting. Macbeth will soon learn what it is to indulge the powers of evil. He has already had a taste thereof in his encounter with Banquo's ghost and has already acted on the ambiguous promises and predictions the evil sisters have made.  

The introduction of Hecate, the goddess of witchcraft and magic, adds to the drama and is portentous. Her presence is an indication of worse things to come; Macbeth's already ruthless and bloody acts assume a new level of atrocity after her address to the weird sisters. He orders the assassination of Macduff's entire family and his servants.

It is clear from Hecate's anger that she saw Macbeth as a juicy fruit, ripe for picking, and that her minions acted without consulting her, thus denying her the opportunity of corrupting him herself.

Hecate makes it clear that what has gone before was mere trifling. She states that

Great business must be wrought ere noon.

Her statement foreshadows Macbeth's later meeting with them. On this occasion he will be inspired to take greater risks, for he will be led to believe that he is invincible and unconquerable. Hecate also states that the meeting will inform Macbeth of his destiny. He, as we know, will be completely misled by the predictions of the apparitions that the witches will summon. His doom is surely sealed. Hecate maliciously, and probably with relish, states:

...shall raise such artificial sprites
As by the strength of their illusion
Shall draw him on to his confusion:
He shall spurn fate, scorn death, and bear
He hopes 'bove wisdom, grace and fear:
And you all know, security
Is mortals' chiefest enemy.

It is clear that the forces of evil have found in Macbeth the perfect vehicle through which to exercise their malice. This scene accentuates the depth the witches' perfidy and their utter confidence that Macbeth will allow himself to be misled and used to fulfill their purpose. 

The answer to this is, of course, a matter of opinion. Certainly the first scene in Act IV, when Macbeth visits the witches and receives a prophecy that none of woman born can kill him has major consequences for the rest of the play. But I would argue that Act IV Scene 3 is the most important in the act. Two significant events occur in this scene. One is that Macduff learns of the death of his wife and children at the hands of Macbeth's assassins. He is from this point sworn to avenge their deaths, which of course he does at the end of the play. The other event is that Macduff forges an alliance with Malcolm, who ascertains Macduff's purity of motives through pretending to be debauched and overly ambitious. The two are, in fact, planning to invade Scotland when Ross arrives with the news of Macduff's unspeakable loss. With the assistance of Macduff and several other thanes, Malcolm launches an invasion that ultimately leads to the overthrow and the death of Macbeth. So Act IV Scene 3 sets a series of events in motion that lead the play to its conclusion.

The messenger arrives at Macduff's castle and issues a warning to Lady Macbeth by uttering the following:

" ... I am not to you known,
Though in your state of honour I am perfect.
I doubt some danger does approach you nearly:
If you will take a homely man's advice,
Be not found here; hence, with your little ones.
To fright you thus, methinks, I am too savage;
To do worse to you were fell cruelty,
Which is too nigh your person. Heaven preserve you!
I dare abide no longer."

The messenger arrives soon after Ross had issued a similar admonition to Lady Macduff. He then left as as quickly as he had arrived, since there was impending danger.

The dramatic purpose of this is to emphasize the degree of turmoil in Scotland at this time. It is to indicate that Macbeth's tyranny has reached such a stage of ruthlessness that he will stop at nothing to ensure that he retains his position. He has also admitted that he is so steeped in blood that there is no return. He has become so paranoid and possessed by evil, that he is left without a conscience. He has become remorseless and has stooped to such a low level that he has no qualms in killing defenseless women and children, as would happen later in this scene.

The messenger's words also juxtapose Macbeth's utter savagery to the kindness and gentleness of the messenger. The humble messenger shows care and concern for Lady Macduff and her children, whereas Macbeth's actions in sending assassins to kill them is a clear display of his callousness. It is ironic that Macbeth should be so heartless towards the family of one of his erstwhile closest friends, a man he accompanied in battle, fighting side by side for the honor of their king. This provides further proof of Macbeth's descent into paranoia and madness. 

In the fourth act of Shakespeare's Macbeth, the influence of the witches has increased so upon Macbeth that Hecate knows he will believe whatever he tells him.  Thus, the treachery of Macbeth is out of control.  The messenger of Scene 2 gives voice to the treacherous plans of Macbeth, who in his evil, does not discriminate among women and children in his killing. 

It is at this point in the drama that the audience senses that Macbeth has given himself over to the powers of the preternatural world. For, he is out of control, acting without any rational thought.  Driven by his lust for power, Macbeth feels that he must kill indiscriminately in order to eliminate any threats to his power. 

Macbeth would have done well to heed the messenger himself as it is only a matter of time before such bloodthirsty leaders are brought down by man or fate.  The reader/audience of today cannot but be reminded of the late Sadam Hussein in this last part of Shakespeare's tragedy.

First, Ross's words as well as the speech of Macduff's son help to further demonstrate how bad things are in Scotland under Macbeth's rule.  Ross says, 

[...] cruel are the times when we are traitors
And do not know ourselves; when we hold rumor
From what we fear, yet know not what we fear,
But float upon a wild and violent sea
Each way and none.

The dramatic element that emerges at the beginning of act 4, scene 3 is a dialogue between Malcolm and Macduff about the state of Scotland.

Shakespeare sets the dreary, dark, and mournful tone of the opening of the act by putting sad and negative imagery into the mouths of Malcolm and Macduff. Malcolm speaks of finding "desolate shade" and weeping "our sad bosoms empty" over the state of Scotland. A sense of heavy hearted pain thus starts the action.

Macduff tries to raise Malcolm's spirits by reminding him they need to use their might to defend the people. He speaks of widows who "howl" and orphans that "cry." He uses the literary device of metaphor—a comparison that does not use the words like or as—to describe the state of Scotland as so bad that it is as if the country will

Strike heaven on the face
until heaven itself cries out in pain.

Dramatically, the opening of this scene pulls back the camera from the tight focus on Macbeth and his concerns to the devastating effects his rule is having on ordinary people in his country. This helps convince us as an audience that swift intervention is vital.

The dramatic element at the beginning of Act 4, sc. 3 is subtle.  Malcolm and Macduff are in England.  Malcolm is there because he fled Scotland after his father, King Duncan, was killed and Macduff is there to help Malcolm drum up support from the English to go to Scotland and unseat Macbeth from the throne. Malcolm is uncertain of Macduff's loyalty though and so Malcolm's words are chosen carefully as he closely watches Macduff's reaction to his words.  He tells Macduff that he'll avenge whatever wrongs have been committed against him or Scotland, but he's careful not to say what those wrongs are.  Then to further test Macduff's loyalty to make sure that Macduff is honest and trustworthy, he tells Macduff that he will be far more terrible than Macbeth.  He says he'll be lustful, greedy, unjust, dishonest and full of every other vice he can think of.  When Macduff says that possessing those qualities makes Malcolm unfit to live, let alone govern Scotland, Malcolm tells him he was just testing Macduff.  Until the reader gets to Malcolm's confession of his "test", the reader doesn't know this is a test, so surprise is another literary element.

Also signficant here is the way that Macduff acts as a foil for Macbeth (and Lady Macbeth, too, perhaps).  His first inclination upon hearing of the death of his family is to grieve. "All my pretty ones? / Did you say all?" he moans. When Malcolm says "Dispute it like a man," meaning go and fight Macbeth, Macduff says "I shall do so;/but I must also feel it as a man" (4.3,216-221). Here we have a new definition of manhood not yet seen in the play. Indeed, Lady Macbeth at the beginning worries that her husband is "too full the milk of human kindness" and would herself dash her babe to the ground in order to carry out the murder of Dunca.  Macduff is both warrior and father and husband, a man who can love as well as fight.

Act IV, Scene 3 begins with Macduff and Malcolm in England.  Malcolm tests Macduff's sincerity by telling Macduff he has done far worse things than Macbeth, but Macduff responds by saying Malcolm is the rightful heir to the throne. Shakespeare uses this to show that Malcolm is a good man and will be a good king for Scotland. When Ross tells Macduff that Macbeth has killed his family, Macduff is even more determined to seek revenge against Macbeth, and he and Malcolm vow that this will be the last evil act of Macbeth. The conversation between Macduff and Malcolm also reinforces a theme of the play as well: that a true king is one who is motivated by his love for his country, and Macbeth's is certainly not a true kingship because it has no moral legitimacy.

Consisting of less than fifteen lines, this scene is very short when compared to others in Macbeth. However, it would be a mistake to think that such a short scene does not have some dramatic purpose and significance. We can see this clearly when it is considered in the wider context of the play.

To see its dramatic purpose, look back to the prophecies shown by the witches in act 4, scene 1. Remember how Macbeth was told by a crowned child that he could not be harmed until Birnam Wood moves to Dunsinane Hill. Taking this at face value, Macbeth believed that he was invincible.

In this scene, the reader sees that this prophecy is about to come true: soldiers commanded by Malcolm, the true heir of Scotland, have used branches to make themselves look like trees. In other words, Birnam Wood really has moved to Dunsinane Hill, although this was not in a way that the reader, or Macbeth, would have expected. On the one hand, this is an example of situational irony, while on the other, it reveals the scene’s dramatic purpose: to show that Macbeth’s tyrannical reign is about to end, just as the witches warned.

This idea is further emphasized by the use of the word “harbinger” in the scene’s closing sentence. A harbinger means that something or someone is about to approach, and the word is often associated with the apocalypse or the end of the world. Looking at Macbeth’s situation, this foreshadows both the end of his reign and the end of his life.

I choose the moment when Macbeth changes his attitude about the possibility of being king from passive to active.  Shortly after the witches' pronouncement, Macbeth says:

If chance will have me king, why, chance may crown me,
Without my stir.

Then, not so very long later, he is in the presence of the King; Duncan has just named  Malcolm as his successor.  At this news, Macbeth says:

The Prince of Cumberland! that is a step
On which I must fall down, or else o'erleap,For in my way it lies.

It's clearly this moment when the audience must realize that Macbeth will be taking action to make the prediction become a reality. 

This is one of those wonderful questions where pretty much anything goes as long as you can justify it, so I am going to disagree with my learned e-colleagues above and state that for me Act I scene i is the most important scene of the play

This is because it completely sets up the setting and foreshadows much of the action - the blasted heath strikes the appropriate sombre tone and the key line "fair is foul and foul is fair" is something that foreshadows many aspects of the plot to come. It also introduces the witches as key characters in the play, emphasising the role of black sorcery and posing an intriguing question: does Macbeth do what he does because of the witches or would he have done it anyway?

I believe that Act II, Scene 1 is important in foreshadowing Macbeth's mental collapse later in the play; however, the most important scene should be the scene that expresses the most conflicting events.  Act 3, Scene 4 is the most important scene in the play because Macbeth is at the high point of his reign, and ironically it is the beginning of his downfall. Shakespeare strategically writes a most interesting scene where Macbeth is receiving guests at his banquet as King, and than moments later is in distress upon seeing Banquo's ghost! You can see the play unravelling before your eyes.

I agree that the most important scene in terms of plot and character development is the first scene in Act II when Macbeth hallucinates the dagger.  The dagger is a symbol of Macbeth's guilt and fear and it is at this moment when he questions and challenges his fate while looking for the right decision to make.  This is Macbeth's "crossroads," the point at which he must decide which path to travel.

I don't necessarily disagree with Post #2, but I think you could also consider Act II, Scene 1.  I don't think the witches force Macbeth to kill Duncan -- I think he is at fault.  So this scene is important because it is where he actually decides to do the deed that will bring his doom.

The most important scene in Macbeth is the scene in which the three hags inform Macbeth (to paraphrase their words) that he will be King. This is the match that set of the conflagration, that led to Lady Macbeth’s plote, that led to the murder of the King:D

This question revolves around an individual's own perception when considering Macbeth and its climax. It depends whether you think the climax is

1. Duncan's murder which reinforces Macbeth's "vaulting ambition."
2. Macbeth's rise to so-called greatness and his realization that Banquo's sons would succeed him not his own thus leading him to more and worse crimes:

"No son of mine succeeding...For them the gracious Duncan have I murder'd..." (III. i. 63- 65)

1. The contribution of the witches and the supernatural in turning the real world into an unnatural world where reality and evil become interchangeable - "fair is foul and foul is fair." The declining sanity

in the paranoid hallucinations and, most markedly, in the insomnia of Macbeth and of Lady Macbeth.

    4. The psychological effect on Lady Macbeth when she has lost her control over Macbeth and longs for that role to resume; ironically as she previously wanted, by her own admittance, to be "de-sexed." She is ony capable of nurturing Macbeth.

 "give me your hand … to bed, to bed, to bed"  (V.i.66-68).

    5. Macbeth's own demise when he is killed by a man not "of woman born."

For me, the climax must come when Macbeth realizes that 

"it is a tale
Told by an idiot, full of sound and fury,
Signifying nothing."(V. v. 26-28)