Can someone explain the context of this monologue from Macbeth?

Question

"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 murdering ministers,
Wherever in your sightless substances
You wait on nature's mischief! Come, thick night,
And pall thee in the dunnest smoke of hell,
Thank my keen knife see not the wound it makes,
Nor heaven peep through the blanket of the dark,
To cry, 'Hold, Hold!'"

I know what it's saying- I just don't know who's saying it, or what the context surrounding it is.

I'm not lazy- I don't have to read the play. I only have to memorize the monologue for an audition. Why bother reading a play I have no interest in if it's not necessary?

Answer 1

Lady Macbeth is the speaker. She has just had word that the King will be stopping at their castle for the night, and is building her courage to follow through with the plot to kill him and install Macbeth as King in his stead.

Answer 2

Lady McB is getting up her courage to murder Duncan.--how come you are too lazy to read Shakespeare's shortest play?