The plot of Macbeth is set in motion ostensibly by the prophecy of the three witches. The prophecy fans the flames of ambition within Macbeth and Lady Macbeth, serving as the primary impetus for the couple to plot the death of Duncan--and subsequently Banquo. But one also wonders: Would Macbeth have committed such heinous crimes if not for the prophecy? What if he had ignored the witches’ statements? Such speculation, however interesting, ultimately appears futile, since the prophecy itself is self-fulfilling. The witches know Macbeth’s tragic flaw: given the irresistible temptation to become King, he will choose to commit murder even though he could simply discard their words. As it turns out, the prophecies are not only fated but fatal, as Macbeth's confidence in the witches leads him to fight a rash battle in the final act. Guilt and Remorse
Some of the most famous and poetic lines from Macbeth are expressions of remorse. “Will all great Neptune’s ocean wash this blood / Clean from my hand?” exclaims Macbeth after he stabs Duncan (II ii 58-59). Similarly, Lady Macbeth is plagued by a “spot” that she cannot remove from her hand: “Out, damned spot! Out, I say. . . What, will these hands ne’er be clean?” (V I 30-37). At first physical remainders of a regrettable crime, the royal blood leaves permanent marks on the psyche of the couple, forever staining them with guilt and remorse. The different ways in which the Macbeths cope with their crimes show how their characters develop: whereas Lady Macbeth is initially the one without scruples, urging Macbeth to take action, it is an overpowering sense of guilt and remorse that drives the Lady to her untimely death. Macbeth, on the other hand, seems to overcome the guilt that plagues him early on in the play. Ghosts and Visions
Just as an overwhelming guilty conscience drives Lady Macbeth mad, so too does Macbeth’s “heat-oppressed” brain project the vision of a dagger before he murders Duncan...