Will all great Neptune's ocean wash this blood clean from my hand?

This line, from Shakespeare's "Macbeth," reflects the protagonist's deep remorse and guilt after committing murder. It suggests that no amount of cleansing or external force, represented by Neptune's ocean, can wash away the internal stain of guilt he feels. The imagery emphasizes the permanence of his actions and the psychological torment that accompanies them, highlighting the theme of guilt and moral consequence in the play. Ultimately, it conveys the idea that some deeds leave an indelible mark on the soul.