Stars, hide your fires; Let not light see my black and deep desires: The eye wink at the hand; yet let that be, Which the eye fears, when it is done, to see. (1.4.55-60) Shakespeare- using hand/eye imagery, shows that even before Lady Macbeth encourages him, Macbeth is already considering murdering Duncan to take his throne. When Macbeth is about to kill Duncan in 2.1, his addled mind hallucinates a floating dagger coated in blood: And on thy blade and dudgeon gouts of blood, Which was not so before. There's no such thing: It is the bloody business which informs Thus to mine eyes. (2.1.54-57)
The “bloody business” is, of course, his plot to murder Duncan while he resides in Inverness, the Macbeths’ castle. His quote explains how before he even commits his crime, his mind is already feeling guilt from his ambition and Lady Macbeth’s prodding and spiteful words. Afterwards, his guilt intensifies to the point where he becomes crazed. In 2.1-2.2, Shakespeare utilizes blood and eye/hand imagery to show Macbeth’s guilt over killing his king. After Duncan is dead, Macbeth retires to his chambers after the deed, covered in blood, and his actions catch up with his mind:
What hands are here? ha! they pluck out mine