Replete with imagery, the second scene of Act II of Shakespeare's Macbeth continues the motif of blood while the ominous sound images of the screeching of an owl, the tolling of bells, and the ironic knocking outside the gate by Macduff, who later kills Macbeth portend the psychological demises of both Macbeth and Lady Macbeth.
The water imagery connects to Macbeth's regret and sense of guilt at having killed Duncan:
What hands are here? Ha! they pluck out mine eyes!
Will all great Neptune's ocean wash this blood
Clean from my hand? No, this my hand will rather
The mutitudinous seas incarnadine
Making the green one red (2.2.74-79)
Clearly, Macbeth is unnerved after his heinous act, suffering great remorse for his act. While Lady Macbeth tells him that some water will wash away the evidence of their act, ironically it is she who loses her mind completely as, obsessed with guilt, she tries to wash away the "spot" of her conscience. Unlike Pontius Pilate, she and Macbeth cannot wash their hands of the affair of Duncan's murder; they are doomed to become the victims of their evil deeds.