"The raven himself is hoarse
That croaks the fatal entrance of Duncan..."
See in text (Act I - Scene V)
Ravens are typically symbols of death or bad omens, creating an ominous atmosphere in a story. Lady Macbeth suggests that the raven's voice is harsh or rough from croaking over the dead bodies on the battlefields, and that it will have reason to croak again at Macbeth's castle with Duncan's fatal arrival.
"Here's a farmer that hanged himself on th’
expectation of plenty...."
See in text (Act II - Scene III)
The Porter, likely still drunk, is imagining what being the gatekeeper of hell would be like and who he would meet. He imagines encountering a farmer who stockpiled his crops to sell at inflated rates during the next famine and then hanged himself when the famine never came. This imaginary farmer represents the sins of greed and suicide, which the Porter thinks would make him a perfect candidate to meet in hell.
"It is an accustomed action with her, to seem(25)
thus washing her hands...."
See in text (Act V - Scene I)
This is an example of Shakespeare including directions to the actors through dialogue rather than stage directions. Lady Macbeth appears to be continuously washing her hands. Ironically, in act II scene II, she tells her husband: "A little water clears us of this deed." Here she is months later still unable to get her hands—or her conscience—sufficiently clean.
"like a giant's robe
Upon a dwarfish thief...."
See in text (Act V - Scene II)
Since clothes often symbolize titles in this play, this simile illustrates how Macbeth is unfit to rule. The clothes and title of king hang about him because he is too small and unfit to wear them.