Guilt and conscience

• “Will all great Neptune's oceans wash this blood clean from my hands?”

  Macbeth’s question reveals that he already feels overwhelmed by guilt and doubts that he can ever cleanse himself of it. The blood on his hands is a metaphor for the moral stain of his crime, suggesting that no external force, even the vast ocean, can rid him of his conscience’s torment. This foreshadows the ongoing mental anguish he’ll endure as he tries to cope with his guilt.
• “Macbeth does murder sleep”

  The voice symbolizes Macbeth’s guilty conscience, warning him that he will no longer find peace. “Sleep” here represents innocence, rest, and mental stability—all of which are lost to him because of his crime. The line foreshadows Macbeth’s descent into paranoia and insomnia, as his conscience will haunt him and deny him any comfort or rest.