Lady Macbeth’s desperation is apparent in her ramblings: to show this, Shakespeare:
uses lots of punctuation to reflect her disjointed mind
uses repetition (“out”) to show her increasing desperation
The use of imperative verbs (“out”) is ironic: whereas earlier in the play she used commanding language with evil spirits, she has now completely lost power. Commands have turned into pleas of desperation
Macbeth echoes the language of Lady Macbeth (“out, out”)
However, unlike other times when Macbeth echoes the language of Lady Macbeth or the witches, this quotation doesn’t imply he is being led by them
Lady Macbeth’s desperation has turned into a reflection of Macbeth:
It is a realisation that what he – and Lady Macbeth – have done was worthless
It creates a sense of pathos for the audience
Macbeth using Lady Macbeth’s words brings the couple closer again