In Macbeth, Shakespeare uses the theme of equivocation to effectively illustrate the evil nature of the witches. Equivocation is the use of ambiguous expressions in order to mislead. The prophecies of the witches play a mischief in this play, as they are a form of deception that at times use vague language to dodge an issue. The three influential prophecies, which the witches make in this play, are that the protagonist Macbeth will become the king of Scotland, Banquo will be the father of the king of Scotland, and Macbeth will not be killed until the Birnam wood moves to Dunsinane hill. The sources of these prophecies are the witches who put together the devious words into Macbeth 's mind, which demonstrates the evil nature of the witches.
In Macbeth, one of the earliest prophecies that the witches make is that Macbeth will become the king of Scotland. "All hail, Macbeth! that shalt be king hereafter!"(I.iii.50) is the prophecy in which no indication of the doom of Macbeth is present. The literal meaning of this apocalypse is that Macbeth will become the king of Scotland. Thus, his ambition to take the pursuit of breaking the natural order to become the king becomes ungovernable. This is evident when Macbeth is shown hallucinating of a dagger before he kills Duncan, the real king of Scotland. Macbeth says, "Is this a dagger, which I see before me, / The handle toward my hand? Come let me clutch thee"(II.i.33-34), which shows that he is in a great doubt on whether to assassinate Duncan or not. The metaphorical meaning of the revelation disclosed by the witches is that Macbeth will ultimately be ruined in the future after he reaches his ambition of becoming the king, as he will have to face the resistance of the loyal nobles of king Duncan including Banquo, Macduff, Malcom, etc. Macbeth is greatly affected by this prophecy and becomes the target of the mendacious and perplexing words spoken by the witches and kills the king.