When a messenger arrived to inform her that Duncan would pass a night in Macbeth's castle, she nerved herself for a very base action.
She told Macbeth almost as soon as she saw him that Duncan must spend a sunless morrow. She meant that Duncan must die, and that the dead are blind. “We will speak further,” said Macbeth uneasily, and at night, with his memory full of Duncan's kind words, he would fain have spared his guest.
“Would you live a coward?” demanded Lady Macbeth, who seems to have thought that morality and cowardice were the same.
“I dare do all that may become a man,” replied Macbeth; “who dare do more is none.”
“Why did you write that letter to me?” she inquired fiercely, and with bitter words she egged him on to murder, and with cunning words she showed him how to do it.
After supper Duncan went to bed, and two grooms were placed on guard at his bedroom door. Lady Macbeth caused them to drink wine till they were stupefied. She then took their daggers and would have killed the King herself if his sleeping face had not looked like her father's.
Macbeth came later, and found the daggers lying by the grooms; and soon with red hands he appeared before his wife, saying, “Methought I heard a voice cry, 'Sleep no more! Macbeth destroys the sleeping.'”
“Wash your hands,” said she. “Why did you not leave the daggers by the grooms? Take them back, and smear the grooms with blood.”
“I dare not,” said Macbeth.