In act 1, scene 3 of Shakespeare's Macbeth, three witches give Macbeth three statements. The first, "Hail to thee, Thane of Glamis!"(1.3.50), is simply a greeting. Macbeth inherited the title of Thane of Glamis from his father, who was killed about fifteen years earlier. Macbeth learns about the second statement, "Hail to thee, Thane of Cawdor!" (1.3.41–52), from Ross and Angus only after the witches leave the scene: Macbeth had been made Thane of Cawdor by King Duncan.

The third statement, a prophecy, is that Macbeth "shalt be King hereafter!" (1.3.53), which comes true after Macbeth murders King Duncan between act 2, scene 1 and act 2, scene 2 and assumes the throne.

Much the same thing happens in act 4, scene 1, when the witches conjure up apparitions which seem to make prophecies to Macbeth. The first of these, made by the First Apparition, "Beware Macduff; / Beware the Thane of Fife" (4.1.79–80), is simply a warning that cautions Macbeth about something he already knows.

MACBETH. Thou hast harp'd my fear aright. (4.1.82)

The second and third of the apparitions' pronouncements are also warnings in the form of cryptic, equivocal, paradoxical, and essentially misleading prophecies. Whereas "Hail to thee, Thane of Glamis," "Hail to thee, Thane of Cawdor," and "thou shalt be King hereafter!" are expressed in act 1, scene 3 in a straightforward, positive way, the prophecies and act 4, scene 1 are expressed ambiguously in a negative way.

SECOND APPARITION: Be bloody, bold, and resolute; laugh to scorn
The power of man, for none of woman born
Shall harm Macbeth. (4.1.87–89)

"None of woman born" is clearly equivocal, and it's clearly meant to mislead Macbeth. The Second Apparition plays on Macbeth's sense of invincibility based on his fulfillment of the prophecy that he "shalt be King hereafter!" (1.3.53). There's nothing in that earlier prophecy to suggest any impermanence in Macbeth's situation or that he will be deposed or killed. Macbeth believes that he's fated to be king and that Fate will protect him and sustain him as king.

Also, the apparition says that "none of woman borne shall harm Macbeth," rather than "one not of woman borne shall harm Macbeth." The prophecy is based on a technicality that Macbeth fails to grasp at the time he hears it. The apparition makes a subtle, equivocal distinction—a distinction known only to the apparition and subsequently exploited by Macduff in act 5—that Macduff "was from his mother's womb / Untimely ripp'd" (5.8.19–20). In other words, Macduff was born by Caesarean delivery. The apparition doesn't exactly lie to Macbeth, but it doesn't exactly tell Macbeth the truth, either; and the apparition lets Macbeth believe what Macbeth wants to believe.

THIRD APPARITION. Macbeth shall never vanquish’d be until
Great Birnam Wood to high Dunsinane Hill
Shall come against him. (4.1.104–106)

The Third Apparition equivocates and plays on Macbeth's sense of invincibility in the same way that the Second Apparition does. The Third Apparition says, "Macbeth shall never vanquish’d be until / Great Birnam Wood..." comes against him, rather than "Macbeth shall vanquish’d be..." when Birnam Wood comes against him.

Macbeth hears what he wants to hear, and what he wants to hear is that he's invincible. "Then live, Macduff. / What need I fear of thee?" (4.1.92), Macbeth says, and "Who can impress the forest, bid the tree/ Unfix his earth-bound root?" (4.1.107–108). Macduff, being born of a woman—or so Macbeth believes—can't hurt him, and Birnam Wood is never going to walk up the hill to Dunsinane Castle.

In act 5, however, Birnam Wood does come to Dunsinane Castle, in the form of Malcolm's soldiers marching up the hill to the castle carrying branches from the trees in Birnam Wood, and Macbeth is killed by Macduff, who is, technically, "not of woman born."

There is one other prophecy made to Macbeth in act 4, scene 1 which isn't spoken to Macbeth but which is shown to him. Macbeth demands to know, "shall Banquo's issue ever / Reign in this kingdom?" (4.1.114–115). The witches show Macbeth a parade of eight kings, all of whom look like Banquo, Macbeth's friend and comrade-in-arms who Macbeth ordered to be killed earlier in the play.

The kings are followed by Banquo himself, who is holding a looking glass that shows many more kings representing Banquo's line of descendants extending into infinity. This line of Banquo's descendants includes a representation of King James VI, the patron of Shakespeare's acting troupe, who believed himself descended from Banquo and for whom Shakespeare likely wrote Macbeth.

King James VI's belief in his ancestry notwithstanding, Duncan's son, Malcolm, not Banquo's son, Fleance, becomes King when Macduff kills Macbeth in act 5, scene 7.

The Weird Sisters (also referred to as witches) make their final appearance in Macbeth in Act IV, Scene 1. In this scene, the Weird Sisters show Macbeth three apparitions that predict his future. The first apparition warns Macbeth to be afraid of Macduff. The second apparition tells Macbeth not to fear any man born of a woman because they cannot harm him. The third apparition says that Macbeth should not worry until Birnam Wood marches to fight him at Dunsinane Hill. These apparitions provide Macbeth with a false sense of security, and he becomes overconfident in his ability to defend his kingship.

In Act V, the predictions of all three apparitions come true. Malcolm's army disguises themselves using branches from Birnam forest. As they approach Macbeth's stronghold, it appears like the Birnam Wood is marching towards Dunsinane Hill. Macduff then confronts Macbeth and mentions that he was "untimely ripped" from his mother's womb, which means he had a Cesarean birth. Macduff then kills Macbeth in a sword fight, meaning the third prediction comes true, too.

In Act IV, Scene 1, the witches summon three apparitions. The first apparition tells Macbeth to beware Macduff. The second apparition tells Macbeth that “none of woman born” shall harm him. The third apparition tells him:

Macbeth shall never vanquish’d be until

Great Birnam wood to high Dunsinane hill

Shall come against him (4.1.92-94).

In Act V, Scene 4, Malcolm orders every soldier to cut down a branch from Birnam Wood to act as camouflage. In Act V, Scene 5, a messenger reports to Macbeth that he thought he saw the Birnam wood begin to move. He saw the troops, draped in branches moving toward Dunsinane. The third prophecy is confirmed. In Scene 8, Macduff challenges Macbeth. The first prophecy is confirmed. Macduff then reveals that he was “untimely” ripped from his mother’s womb. He was born by Caesarean-section. Finally, on a verbal technicality, the second prophecy is confirmed when Macbeth is killed by Macduff.