Macbeth's soliloquy contains some of the most famous, if depressing, metaphors in any of Shakespeare's plays, indeed all of English literature. Upon learning of his wife's death, he compares human life to a "brief candle," which is snuffed out after burning for a short time. He goes on to describe life even more bleakly, as an actor, and then as a senseless, meaningless story:
Life's but a walking shadow, a poor player
That struts and frets his hour upon the stage
And then is heard no more. It is a tale
Told by an idiot, full of sound and fury,
Macbeth also uses repetition ("tomorrow and tomorrow and tomorrow") to describe time, and life itself, as essentially meaningless, nothing more than time marching on. Shakespeare employs these literary devices to underscore the existential bleakness of Macbeth's mood at the end of the play.
This soliloquy and existential reflection of Macbeth seems somewhat incongruous with his murderous path except that it indicates his deep love for and attactment to Lady Macbeth. Indeed, it is this love for his wife which gives Macbeth pause. For, as he feels his life propelled by his "vaulting ambition," he now realizes the nothingness of his life without his wife and anyone to give it meaning. In its expression, Macbeth's soliloquy contains some literary devices:
As he ponders the meaning, or lack of meaning, in life, Macbeth repeats the word tomorrow in order to suggest the passage of time. He personifies this word of time, too, suggesting that it "Creeps." Likewise, there is personification with "yesterdays" who have lighted the way to death for fools, and with "Life" that is described as being like an actor who "struts" and "frets."
"Life" is also part of a metaphor, an unstated comparison that evokes similarities between one's life and "a walking shadow and "a poor player" on a stage.
The final lines are also metaphoric as life is compared to an idiotic story:
....It is a tale
Told by an idiot, full of sound and fury
- Repetition and Alliteration
Repetition of the word "tomorrow" adds effect and suggests the passage of time. The alliteration of the /t/ also speeds up the line. In line 25, "dusty death" exemplifies also alliteration and "Out, out" is not only repetition, but also assonance, the repetition of a vowel sounds, /ou/
Life, Macbeth contends, signifies nothing without one to share this life. His soliloquy, then, is a deeply regretful one as he has lost his partner in life and ambition.