can't kill him. Then Lady Macbeth questions his manhood and convinces him that he must kill Duncan. Macbeth might have backed down if Lady Macbeth's ambitions hadn't been greater than his own at that time. Lady Macbeth was afraid that Macbeth's nature was too full "of the milk of human kindness". After the murder of Duncan, Macbeth is shaken, forgetting to leave the daggers beside the guards.

Macbeth decides to kill Banquo and his son because they are a threat to Macbeth's future as king. At this point, Macbeth has become a cold-blooded killer who will do anything to keep what he wants. Macbeth doesn't even tell Lady Macbeth about Banquo's murder; he has it done by hired killers without consulting her. He doesn't even take into consideration that Banquo is his friend, and he is truly blind with ambition.

Compare and contrast the murders of Banquo and Duncan Well, a fully developed comparison would involve a bit more context. What are you comparing about these actions?

In general, though, you could say the following things about the two crimes. Macbeth murders Duncan himself (with his wife's urging/help). Banquo is killed by people Macbeth has set to the task. As a result, Banquo's murder is much riskier politically. Duncan is murdered in Act II; Banquo is murdered in Act III. After Duncan is murdered, Macbeth seems to hold it together pretty well; he blames the guards. After Banquo is murdered, Macbeth about loses it in public. After both murders, Macbeth's mind is disturbed. After both murders, the natural order of things is disturbed. That should be enough to get you started on this question, yes? Greg

Shakespeare almost uses Banquo's murder as a foil to the original murder of Duncan.  By comparing the two, the audience can truly see how embroiled in his own schemes Macbeth has become and also the full degree of his ruthless commitment to achieving his ambition.  Macbeth had many doubts about carrying out Duncan's murder and had to be prodded and convinced by Lady Macbeth to carry it out.  Even with all of her persuasion, Macbeth is still worried about the moral repercussions of such an act, doubting his role as murderer:

"First, as I am his kinsman and his subject, Strong both against the deed; then, as his host, Who should against his murderer shut the door,(15) Not bear the knife myself" (I.vii. 13-16)

Clearly, Macbeth has reservations about carrying out Duncan's murder.  He doubts his ability to execute the deed and is plagued with self-doubt and feelings of guilt and possible recrimination. 

Contrastingly, Macbeth's attitude has become much more cut-throat (no pun intended!) the second time around when he plans Banquo and Fleance's murders.  Shakespeare uses these scenes to show the audience how much more comfortable Macbeth has become in his role as murderer; he now confidently plans their deaths and hires the hitmen himself, with no prodding or convincing required by Lady Macbeth.  He has taken matters into his own hands; Macbeth's detachment from his earlier moral stance becomes evident in his later conversation with the head murderer:

"Thou art the best o’ the cut-throats! Yet he's goodThat did the like for Fleance. If thou didst it,Thou art the nonpareil" (III.iv.18-20).

In Banquo's death, Macbeth is much more at ease-- he practically celebrates the fact that Banquo has been killed and then mourns the fact that Fleance escaped.  His response to his former ally's murder reveals how far Macbeth has slipped in terms of morality.  His ambition for the throne has blinded him to the moral wrongness of murder.

Both Banquo and King Duncan are depicted as honorable, morally upright men who become victims of Macbeth's ambition and violence. The two men are revered throughout Scotland and respected by their peers. King Duncan is viewed as a gracious, honorable king, while Banquo is viewed as a valiant, loyal soldier. In addition to their positive reputations and honorable personalities, they both trust Macbeth and consider him a close friend. Both men also have sons who manage to escape Macbeth's wrath. Macbeth views both men as obstacles standing in his way of attaining the Scottish throne and cementing his legacy.

Despite their many similarities, Banquo occupies a much lower status than King Duncan. In addition, King Duncan is depicted as naive and gullible, while Banquo is portrayed as discerning and cautious. King Duncan is also depicted as a compassionate, gentle person, while Banquo is known for his brutality on the battlefield. Banquo is suspicious of Macbeth, while King Duncan is completely unaware that Macbeth is plotting his assassination. Macbeth also murders King Duncan on his own, while he orders assassins to kill Banquo. Banquo received a favorable prophecy from the three witches, while King Duncan never interacted with them.

Banquo and Duncan do share some similarities in Macbeth as well as having their fair share of differences.

Similarities:

Both characters have noble personalities and are essentially good  men.

Both characters are murdered, or arranged to be murdered, by Macbeth.

Macbeth sees visions, or has hallucinations in relation to both characters.  Before Duncan's murder, he sees a floating dagger, and after Banquo's murder, he sees a bloody-looking Banquo ghost sitting at the banquet table.

Both Duncan and Banquo had sons.

Differences:

Station:  Duncan was king, while Banquo was predicted by the witches that his sons might be king.

Macbeth murdered Duncan directly, while with Banquo he hired murderers.

Throughout the play, Banquo is portrayed as a loyal, level-headed individual who becomes a victim of Macbeth's unchecked ambition. Like Macbeth, Banquo is also a valiant soldier who courageously fights against the Irish and Norwegian troops at the beginning of the play. Banquo also receives a prophecy from the witches but reacts differently to their message. Banquo is more discerning than Macbeth and exercises caution after hearing his prophecy. Banquo is also curious about his future but does not act upon his prophecy. Unlike Banquo, Macbeth acts upon his prophecy, which leads to his downfall. Macbeth is negatively influenced by his ambitious wife and ends up murdering King Duncan. Macbeth then becomes a bloodthirsty tyrant who kills Banquo and Macduff's entire family. Macbeth's unchecked ambition leads to his downfall, and he is eventually killed in battle by Macduff.

Macduff is much more of an action type of person. He is quick to draw conclusions, and this is seen in the way he appears to be the first to suspect that Macbeth had something to do with the murder of Duncan. Macduff was suspiciously absent from the coronation and banquet to honor Macbeth, which lends to the idea that he believes Macbeth guilty of the murder. Macduff is also putting the political climate's safety before that of his family. He leaves his wife and son, knowing Macbeth is a danger to them, to assemble troops to fight him.

Banquo, on the other hand, seems to possess much more virtue in the way of his attitude toward family and friends. Sadly, this is his downfall. Macbeth is his friend, and he is dismissive of the witches and their predictions at first, and tried to caution Macbeth to do the same. He is not a stupid man, he just trusted the wrong person. When he finally comes to realize that Macbeth means to do him harm, he is devastated-"As the weird women promis'd, and I fear/ Thou play'dst most foully for't"(act III, i). Banquo is also a more protective father than Macduff. When the murderers come, he commands Fleance to leave him and save himself.

In William Shakespeare’s play Macbeth, Banquo and Macduff can be compared and contrasted in a number of ways, including the following:

• Banquo first appears as the friend of Macbeth, and some critics think he shares with Macbeth the trait of ambition. Macduff, however, never seems ambitious for himself.
• Banquo suspects that Macbeth may have killed Duncan in order to become king, and Macduff very quickly has the same suspicions.
• Macbeth succeeds in having Banquo killed so that Banquo will not pose a threat to his own power; he fails, however, to have Macduff slain, and it is Macduff who ultimately kills Macbeth.
• Macbeth succeeds in having Macduff’s family slain, but he fails to have Banquo’s son slain.
• Banquo is present at the banquet Macbeth holds after Duncan’s death – or, at least he is present in Macbeth’s own mind and imagination. Macduff, however, deliberately does not attend the banquet.
• Macduff’s opposition to Macbeth puts Macduff’s family at danger; Banquo’s potential as a rival to Macbeth puts Bandquo’s son at danger.
• Both Banquo and Macduff are mentioned in prophecies by the witches – prophecies that trouble Macbeth. As a result of these prophecies, Macbeth takes hostile action against both men.
• Macduff is widely seen as one of the most virtuous characters in the play. Banquo is also considered a virtuous character, but his virtue has come into greater question than Macduff’s.
• Both Banquo and Macduff triumph over Macbeth in ways that Macbeth does not suspect. Thus, Banquo, because his son survives Macbeth’s attempted murder of them both, becomes the ancestor to a long line of kings, just as the witches had prophesied but not in the ways Macbeth had expected. Likewise, the witches had prophesied that Macbeth would never be slain by a man born of a woman. He therefore assumes, during his closing battle with Macduff, that he is invincible:

Macbeth.Thou losest labour:  As easy mayst thou the intrenchant air  With thy keen sword impress as make me bleed:  Let fall thy blade on vulnerable crests;  I bear a charmed life, which must not yield,  To one of woman born.

He is surprised, therefore, when Macduff replies:

Macduff.Despair thy charm;  And let the angel whom thou still hast served  Tell thee, Macduff was from his mother's womb  Untimely ripp'd.

In other words, Macduff was born as a result of a Caesarian section.  In short order, then, Macduff not only slays Macbeth but beheads him. Macduff is a hero in the play in ways that Banquo never has a chance to be.

This is an interesting question. Shakespeare obviously intended to have Banquo and Macbeth be foils. Banquo is calm, patient, intelligent, rational, and conservative, while Macbeth is emotional, rash, ambitious, impulsive, more a man of action than a thinker, and not completely sane. Macbeth is dominated by his wife, while Banquo's wife is never mentioned. He may be a widower. The two men have equal status before Macbeth murders Duncan and becomes king. After that, Banquo treats him with formal courtesy and deference, although he feels certain that Macbeth was responsible for Duncan's death.

Both men believe in the prophecies of the Three Witches they met on the moor, but Banquo is content to wait without trying to take a hand in changing history; whereas Macbeth is only encouraged to go ahead with what he has already been planning.  Banquo believes in loyalty and tradition, while Macbeth seems relatively indifferent to such values. A comparison might be made with Hamlet and Laertes, with Banquo resembling the more intelligent and conscientious Hamlet and Macbeth resembling the rash, emotional, impetuous Laertes.

Macbeth himself offers the best comparison between himself and Banquo in Act 3, Scene 1.

Our fears in BanquoStick deep; and in his royalty of natureReigns that which would be fear'd: 'tis much he dares;And, to that dauntless temper of his mind,He hath a wisdom that doth guide his valourTo act in safety. There is none but heWhose being I do fear: and, under him,My Genius is rebuked; as, it is said,Mark Antony's was by Caesar. He chid the sistersWhen first they put the name of king upon me,And bade them speak to him: then prophet-likeThey hail'd him father to a line of kings:Upon my head they placed a fruitless crown,And put a barren sceptre in my gripe,Thence to be wrench'd with an unlineal hand,No son of mine succeeding. If 't be so,For Banquo's issue have I filed my mind;For them the gracious Duncan have I murder'd;Put rancours in the vessel of my peaceOnly for them; and mine eternal jewelGiven to the common enemy of man,To make them kings, the seed of Banquo kings!

The "Caesar" Macbeth is referring to in this soliloquy is not Julius Caesar but Octavius Caesar, whose relationship with Mark Antony is dealt with at great length in Shakespeare's Antony and Cleopatra. In that play Antony is portrayed as emotional, sensuous, impulsive, reckless and devoted to a manipulative woman, while Octavius is portrayed as wise, thoughtful, patient, cunning, cautious, and coldly realistic. A very good comparison can be made, following Shakespeare's own suggestion, between Banquo and Octavius, on the one hand, and Macbeth and Antony, on the other. Just like Macbeth, Antony recognizes that Octavius is superior to him in many important respects. Like Macbeth, Antony is somewhat afraid of Octavius, although he is too noble to think of trying to have him assassinated. In Act 2, Scene 3 a Soothsayer warns Antony that he should stay away from Octavius, and Antony reflects:

Be it art or hap,He hath spoken true: the very dice obey him;And in our sports my better cunning faintsUnder his chance: if we draw lots, he speeds;His cocks do win the battle still of mine,When it is all to nought; and his quails everBeat mine, inhoop'd, at odds. I will to Egypt:And though I make this marriage for my peace,I' the east my pleasure lies.

We all know people who make us feel self-conscious and inferior. We are wise to stay away from them.

In certain ways, we can read Banquo as serving the role of a foil for Macbeth in William Shakespeare’s play, Macbeth. Both men are of roughly equal stature in the kingdom and both show valour in battle. When the weird sisters appear, though, they react differently. Banquo reacts as a good Christian should and is worried that they are evil, and thus that listening to their prophecies, even if the prophecies are true, must have a bad effect. Macbeth, however, is seduced by the promise of power and kills Duncan and eventually Banquo. It is not entirely obvious whether Banquo is actually more virtuous than Macbeth or merely less brave, though.