Can you explain this quote from Macbeth?
The raven himself is hoarse
That croaks the fatal entrance of Duncan
Under my battlements. Come, you spirits
That tend on mortal thoughts, unsex me here,
And fill me from the crown to the toe top-full
Of direst cruelty. Make thick my blood.
Stop up the access and passage to remorse,
That no compunctious visitings of nature
Shake my fell purpose, nor keep peace between
The effect and it! Come to my woman’s breasts,
And take my milk for gall, you murd'ring ministers,
Wherever in your sightless substances
You wait on nature’s mischief. Come, thick night,
And pall thee in the dunnest smoke of hell,
That my keen knife see not the wound it makes,
Nor heaven peep through the blanket of the dark
To cry “Hold, hold!
This quote is a speech by Lady Macbeth, wife of Macbeth. In this play, Lady Macbeth urges her husband to kill Duncan, the king of Scotland, so that they might usurp the throne. In this particular speech, Lady Macbeth enacts a kind of prayer (though not to God and Heaven, but to "spirits" and "thick night"), asking for the strength and the cruel indifference needed for her and her husband to commit murder. Though this is the basic meaning of these lines, there is an interesting trope of secrecy or trickery also present throughout the passage. For example, she asks to be "unsexed," which would rid her of her womanly softness but which also creates an image of uncertainty or unclarity about her gender (something that has been "unsexed" is neither male nor female, and a reader might expect Lady Macbeth to be soft and feminine because of her sex, but her womanly outside now conceals a darker, cruel inside). Similarly, she wishes for her "milk," which would be nurturing and sweet, to turn to "gall." The spirits she prays to are "sightless," and she wishes that Heaven might not be able to "peep through the blanket of the dark," again echoing a sense of secrecy and concealment. This speech speaks to Lady Macbeth's cruelty and deceitfulness throughout the play, as she seeks to manipulate all the characters, including her husband.
Lady McBeth foreshadows her eventual madness with several hints of her true nature, which she only wishes were bolder, crueller; first, as the other person answering this question says, by asking that her feminine side be taken away, two, that she not feel remorse for what she is planning, three, that she not even be fully aware of what she does, that is, that she do it in the blackest darkness.
I think she believes her husband to be a weakling, and has decided they will never advance except by her manipulation. Therefore, she must be the man, and here she is asking for the wherewithal.
However, although she steels herself to kill Duncan, she can't maintain the desired attitude toward her crime. Guilt and fear overwhelm her. Is Shakespeare saying that a woman cannot be like a man, cannot turn her 'milk to gall,' or does he believe this crime would weigh upon anyone?
This speech is taken to show Lady McBeth's terrible nature, but I think the interpretation is a little deeper.