How does Macbeth repeat the word sleep and use it in different contexts? Why is this significant?

Shakespeare utilizes the motif of sleep throughout Macbeth on many different occasions. Most famously noted is immediately following the murder of King Duncan when Macbeth reports a spooky occurrence that he experienced during the murder when the two others sleeping in the chamber called out in their sleep that "Macbeth murdered sleep." Further, after murdering Duncan, Macbeth reports "Macbeth will sleep no more." This is coupled with the use of sleep as symbolic of murder with reference to Duncan himself. In this scene, the motif of sleep represents two different but related things. First, sleep is the endless rest that overtakes Duncan when Macbeth murders him. This sleep is important because it represents the life that Macbeth takes away with his evil act. Next—and more significantly—sleeplessness signifies the guilt that Macbeth will face due to evil act he committed. When Macbeth acknowledges that he will no longer sleep, he accepts that the evil act he has committed has truly changed his character. This sleeplessness continues throughout the play as Macbeth and Lady Macbeth descend into madness. Lady Macbeth sleepwalks as one of her final acts before she commits suicide, and Macbeth stops sleeping because he can no longer find rest in the actions that he's committed.