Is this a dagger which I see before me,
The handle toward my hand? Come, let me clutch thee.
I have thee not, and yet I see thee still.
Art thou not, fatal vision, sensible
To feeling as to sight? or art thou but
A dagger of the mind, a false creation,
Proceeding from the heat-oppressed brain? (2.1)
In Act 2, Scene 2, Lady Macbeth confesses to her husband that could not perform the murder because "Had he not resembled / My father as he slept, I had done't." So Macbeth follows through with the killing. Immediately he is striken with guilt as he exclaims, looking on his hands, to his wife, "This is a sorry sight," and "I had most need of blessing." At this point Lady Macbeth reveals the direction of the play with her response: "These deeds must not be thought / After these ways; so, it will make us mad." The crime continues to haunt Macbeth: "Methought I heard a voice cry 'Sleep no more! / Macbeth does murder sleep'" and "'Glamis hath murder'd sleep, and therefore Cawdor / Shall sleep no more; Macbeth shall sleep no more.'" He acts as a type of his wife's subsequent reaction - where fate is leading -- when, alarmed by a knock at the door, he exclaims: "Will all great Neptune's ocean wash this blood / Clean from my hand?"
The next morning Macduff and Lennox arrive to awaken the king. Lennox relates the strange happenings of the evening:
The night has been unruly: where we lay,
Our chimneys were blown down; and, as they say,
Lamentings heard i' the air; strange screams of death,