With the tragic flaw of "vaulting ambition," Macbeth is led into a series of bloody and phantasmagoric experiences, insomnia, moral turpitude, and madness. By Act V, Macbeth begins to unravel, and the use of literary techniques illustrates well this unravelling.
In Scene 3 Macbeth has been given reports by his soldiers, and when a servant reports to the king that there are "ten thousand" soldiers [probably a hyperbole] approaching, Macbeth vents his own fear and emotion upon the servant, ordering him to leave because his "linen cheeks [figurative language] of thine/Are counselors [personification] to fear" (5.3.16-17). Then, Macbeth calls for Seyton, another servant. But, before the man arrives Macbeth speaks to him, saying that he is "sick at heart" [figurative language]; further, he reflects that he has lived enough, having fallen "into the sear,"[figurative language for a withered state.] After this, he compares himself to a "yellow leaf" [a stated metaphor, Macbeth=yellow leaf].
When the physician enters, Macbeth inquires of Lady Macbeth's condition. The doctor informs Macbeth that she is not physically ill; however she is troubled with "thick-coming fancies," [figurative language for her mental delusions]. Macbeth responds by asking,
Canst thou not minister to a mind diseased,
Pluck from the memory a rooted sorrow, [implied metaphor: mind=garden]
Raze out the written troubles of the brain... [implied metaphor: brain=mental tablet on which memories, worries, etc. are recorded]
Cleanse the stuffed bosom of the perilous stuff [implied metaphor: Lady Macbeth's heart = "stuffed bosom"; figure of speech: that which bothers her="perilous stuff"]
Which weighs upon the heart? (5.3.40-44)
Then the physician informs Macbeth that the army approaching can be heard. Macbeth orders his armor and declares that he will not be afraid of death and bane unless "Birnam Forest come to Dunsinane"; that is, until the witches prediction that the forest will move [personification]. But, despite his show of bravado, the literary devices employed in his speeches reveal that Macbeth is fearful as he personifies the cheeks of the servant who reports that the enemy approaches as "counselors to fear. Also, Macbeth perceives himself as "a yellow leaf" who is withering and losing its strength. He is also worried about both himself and Lady Macbeth because he is "sick at heart."