Some important literary devices at work in Act 2 Scene 2 of Macbeth are as follows:
Symbolism: Near the beginning of the scene, Lady Macbeth claims that she heard an owl shrieking, and she calls it the "fatal bellman." The owl is a symbol for the death of Duncan.
Allusion: Later in the scene, Macbeth refers to "great Neptune's ocean" which is a reference to the Roman god of the sea.
Metaphor: Lady Macbeth is disappointed in her husband's cowardice and says, "I shame to wear a heart so white." The color white is a metaphor for fear and innocence.
Extended metaphor: Macbeth talks of "murdering sleep" throughout the scene. He uses sleep as a metaphor for peace, meaning that since he has committed such an evil crime, he will no longer have peace of mind.
Irony: Later the audience learns that the knocking on the door is from Lenox and Macduff who are arriving at Inverness. However, Macbeth is in a state of frenzy and believes that someone has heard him commit the murder--the audience, however, is fully aware that no one else knows of Macbeth's crime.
Dramatic Irony-Macbeth mentions to his wife that the chamberlains were shouting, "Sleep no more! Macbeth does murder sleep" (Act II, Scene 2, lines 35-36). He then insists that he hears knocking, and Lady Macbeth also hears noises. The audience realizes that the noises and Macbeth's belief that the chamberlains commented on his actions are simply figments of the characters' imaginations.
Personification-Macbeth laments about the chamberlains saying that he murders sleep. Macbeth then personifies sleep by referring to it as being "innocent." Innocence is a human attribute, and sleep cannot be innocent because it is not a being.
Metaphor-Macbeth refers to sleep as "great nature’s second course, chief nourisher in life’s feast" (Act II, Scene 2, lines 39-40).
Simile-Macbeth refuses to return to Duncan's chamber to place the daggers next to the chamberlains. Lady Macbeth uses a simile by comparing the dead chamberlains to pictures. She says, "The sleeping and the dead are but as pictures. 'Tis the eye of childhood that fears a painted devil" (Act II, Scene 2, lines 53-55).
Hyperbole-Macbeth looks at his blood-stained hands and employs a hyperbole when he comments, "Will all great Neptune’s ocean wash this blood clean from my hand? No, this my hand will rather the multitudinous seas incarnadine, making the green one red" (Act II, Scene 2., lines 60-64).
Litotes-Lady Macbeth uses a litotes when she says, "A little water clears us of this deed. How easy is it, then!" (Act II, Scene 2, lines 67-68). She drastically underestimates the impact of the crime on their conscience.