In Shakespeare's "Macbeth," the quote "A little water clears us of this deed" reflects Macbeth's initial belief that the act of killing King Duncan can be easily washed away, both literally and metaphorically.
However, as the play progresses, the idea of cleansing oneself of guilt proves to be a false hope. Macbeth and Lady Macbeth grapple with intense feelings of remorse and paranoia that water cannot wash away.