Humans spend over one-third of their lives sleeping. Research shows that sleep helps the body remove toxic waste and refresh the mind. Thus, it makes sense for Shakespeare to use the symbol of sleep in his play Macbeth; in which he writes almost every character an interaction with sleep. Shakespeare’s use of this symbol to represent innocence and peace adds dramatic tension and serves as a clear indicator of a character’s conscience. 

Different authors often have varying interpretations on sleep, so Shakespeare first uses King Duncan’s sleep to establish to readers what sleep will represent—innocence and purity—throughout the play. As Macbeth and Lady Macbeth initiate their plan to kill King Duncan, Lady Macbeth laments on her decision not to kill Duncan herself, saying, “Had he not resembled / My father as he slept, I had done ’t” (Shakespeare II.ii.12-13). Lady Macbeth’s inability to kill Duncan rests partly in the fact that his sound sleep reminded her of her father. She, perhaps unconsciously, associates sleep with innocence and goodness. Readers can see that this innocence temporarily appealed to her basic sense of morality, overcoming even her blinding ambition . Macbeth previously describes Duncan as someone, “So clear in his great office” (Shakespeare I.vii.18). King Duncan is a virtuous, wholesome person, so Shakespeare allows him to sleep soundly to show readers that sleep represents a clear conscience. This is also Shakespeare’s method of depicting a good king- someone who can sleep at night is someone who is at peace. 

Because sleep represents clear thoughts and a restful attitude, Shakespeare delightfully disables Macbeth and Lady Macbeth’s ability to sleep in order to emphasize to readers that their actions were indeed wrong. Macbeth hears a voice after he kills Duncan that says, “Glamis hath murdered sleep, and therefore Cawdor / Shall sleep no more. Macbeth shall sleep no more” (Shakespeare II.ii.45-46). Macbeth previously lamented the need to kill Duncan, finding that the only reason he planned to do so was “blinding ambition.” As a result, readers may have sympathized with his decision to kill Duncan; after all, he faced pressure from a manipulative wife who questioned his manliness. 

However, Shakespeare makes it clear to readers that Macbeth’s actions were not justified in any manner by preventing Macbeth from sleeping. Furthermore, after killing Banquo, Macbeth attempts to sleep by saying, “What's done cannot be undone. / To bed, to bed, to bed” (Shakespeare V.i.74). Macbeth clearly wishes to clear his conscience by sleeping, but he is unable to do so. This once again makes it clear to readers who may have been doubting if Macbeth’s actions were wrong because he didn’t physically kill Banquo: Shakespeare emphasizes that Macbeth’s actions were indeed evil. 

The last instance of sleep occurs as Lady Macbeth hallucinates during her sleepwalking; this depicts her persisting guilt and illusion of sleep. First, she says, “Out, damned spot! Out, I say!—One, two. Why, then, ’tis time to do ’t” (Shakespeare V.i.25). She clearly is unable to “rinse” the guilt off of her, but the fact that this occurs in her sleepwalk is significant because sleepwalking is often seen as a fake sleep. Lady Macbeth has not done anything evil for a while, thus her apparent ability to sleep, but Shakespeare shows readers that guilt is everlasting in only allowing Lady Macbeth to partially sleep. Furthermore, the gentlewoman says, “Ay, but their sense is shut” (Shakespeare V.i.26). The gentlewoman knows that when Lady Macbeth is sleepwalking, she is unable to think or process things. This further emphasizes the false sense of sleep: Lady Macbeth is technically unable to think, thus looking like sleep, but in reality, she has lucid visions and is talking. 

Sleep plays a vital role in Macbeth because Shakespeare heavily uses it to expose the wrongfulness of some characters’ actions.