Come, you spiritsThat tend on mortal thoughts, unsex me here,And fill me from the crown to the toe top-fullOf direst cruelty. Make thick my blood.Stop up the access and passage to remorse,That no compunctious visitings of natureShake my fell purpose, nor keep peace betweenThe effect and it! Come to my woman’s breasts,And take my milk for gall, you murd'ring ministers,Wherever in your sightless substancesYou 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 darkTo cry “Hold, hold!”
After her belittling tirade, Macbeth says this to her:
Bring forth men-children only,For thy undaunted mettle should composeNothing but males.
Her strength does no absolve Macbeth from his actions, but she is certainly one of the driving forces behind them.