Its first ten lines reveal this scene’s purpose. A woman explains Lady’ Macbeth’s sleepwalking. It appears that the emotional impact of her role in the murders is taking a toll on her. Moreover, Lady Macbeth's speech is unstable and incoherent. The one-time domineering lioness of the Macbeth’s castle has been reduced to a shell of her former self. She is not able to communicate effectively; instead, her condition has deteriorated. Lady Macbeth cannot explain her thoughts with coherent sentences, rendering her statements senseless. She cannot even remember events in correct chronological order. To sum up Lady Macbeth's troubles, she says that “all the perfumes of Arabia will not sweeten this little hand.” This means that there is nothing that can be done to reverse her dysfunction.
When Lady Macbeth says, “What's done cannot be undone,” she is resigned to her destiny. Lady Macbeth has made her bed, and now she must lie in it. When Lady Macbeth is taken to the doctor for a medical examination, the doctor says Lady Macbeth needs a divine — not medical — cure. At this point, only God that can forgive Lady Macbeth and give her peace of mind.