In a superlative drama such as Macbeth it seems appropriate that exaggeration should be employed. Certainly, after Macbeth commits the mammoth crime of regicide, it is appropriate that hyperbole, deliberate exaggerations or overstatements, are used by Shakespeare to denote the magnitude of this act by Macbeth and to raise the action to that of high drama.
Here are two further examples of hyperbole:
1. In Act I, Scene 5, Lady Macbeth reads of Macbeth's success in the battlefield and his subsequent promotion. Macbeth also writes to her that three witches have predicted that he will be king. But, Lady Macbeth fears that her husband will have too much of the "milk of human kindness" to go after the crown and be king as the witches have predicted. So, after the messenger departs, she invokes the spirits to come to her and unsex her. In her speech Lady Macbeth employs hyperbole:
The raven himself is hoarse
That croaks the fatal entrance of Duncan
Under my battlements. (1.5.38-40)
Lady Macbeth uses an exaggeration in describing the raven as having croaked so much about the entrance of King Duncan that he has lost his voice. As an omen of death, the raven is hoarse from predicting Duncan's death for so long. Now Duncan's time is up.
2. In Act IV, Scene 3, Macduff alludes to Macbeth in hyperbolic expression:
Not in the legions
Of horrid hell can come a devil more damned
In evils to top Macbeth. (4.3.55-57)
In order to express the wickedness and evil that Macbeth possesses, Macduff describes Macbeth's evil as superlative to that of a devil in "horrid hell" itself.