How we cite our quotes:
BANQUO You should be women, And yet your beards forbid me to interpret That you are so. (1.3.1)
"Should" be: why? Because they look like women, or because they're obviously supernatural? And does the presence of a beard automatically disqualify someone from being a woman? (Don't tell the moustache-bleaching industry.)
FIRST WITCH I will drain him dry as hay: Sleep shall neither night nor day Hang upon his pent-house lid; He shall live a man forbid: Weary se'nnights nine times nine Shall he dwindle, peak and pine: Though his bark cannot be lost, Yet it shall be tempest-tost. (1.3.4)
Here, the First Witch says that she's going to punish a sailor's wife by "drain[ing] [the sailor] dry as hay," which means that she's going to make the sailor impotent: no children, and no sex. Macbeth is definitely worried about male impotence—even Lady Macbeth makes a jab at her husband about it. Is that just a low blow, or does Macbeth actually associate sexual potency with masculinity?
LADY MACBETH Glamis thou art, and Cawdor; and shalt be What thou art promised: yet do I fear thy nature; It is too full o' the milk of human kindness To catch the nearest way: thou wouldst be great; Art not without ambition, but without The illness should attend it: […] Hie thee hither, That I may pour my spirits in thine ear; And chastise with the valour of my tongue All that impedes thee from the golden round, Which fate and metaphysical aid doth seem To have thee crown'd withal. (1.5.1)
According to Lady Macbeth, her husband is ambitious, but he's also too "kind" to do what it takes to murder Duncan so that he, Macbeth, can be king. So what's a wife to do? Lady Macbeth plans to "chastise" Macbeth with the "valour of [her] tongue," which is another way of saying she's going to nagged her husband into taking action so he can be "crown'd withal." This speech establishes Lady Macbeth as the dominant partner in the relationship, which inverts typical 17th century gender and social roles. Since husbands were supposed to "rule" their wives in the same way that kings ruled countries, Lady Macbeth's plan is just another version of treason: taking power that doesn't belong to you.