Sleep is a period of rest and revitalization, without it, a person will become very weak and start to go insane. The story of Macbeth, written by William Shakespeare in the Elizabethan, tells the tale of a man who was tempted by weird sisters to ambition and a greed for power. Macbeth killed the king to gain his throne. However after the murder Macbeth is unable to sleep properly. Sleep is one of the key images which recur throughout the play. Sleep imagery in Macbeth is used to develop the theme of innocence, nature, conscience and guilt and reinforces the images of night, darkness, and evil.
Sleep is a symbol of innocence and goodness, one of the main themes in the play. Since Macbeth has done a deed of great evil, murdering Duncan, Macbeth is no longer innocent. And hence he is no longer allowed to sleep. Macbeth also realizes this himself after the murder and says, "[Macbeth] has murdered sleep, and therefore, Macbeth shall sleep no more" (II.ii.39-40).
Lady Macbeth by George Cattermole.
English: Poster of Thos. W. Keene in William Shake...
The sleepwalking Lady MacbethLady Macbeth is also an evil character and so she also can't sleep properly. The actions which depict her as an evil character are beckoning evil "spirits/ That tend on mortal thoughts" (I.v.39-40) and persuading her husband to kill Duncan after Macbeth has resolved not to do it after thinking it through.
Macbeth and Lady Macbeth's lack of sleep shows the guilt, which they are feeling and how much the murder of Duncan goes against their conscience. The lack of sleep is part of the punishment for Macbeth and Lady Macbeth for killing Duncan, as there is always a penalty for evil actions. This penalty was foreshadowed by the witches when they were plotting to punish the sailor by not letting him sleep and so "sleep shall neither night nor...