The scene where this statement is perhaps most true is in Act I, Scene 7. Macbeth is clearly tormented by his conscience, and after contemplated the gravity of the murder of Duncan, he has decided not to go through with it. Lady Macbeth enters the scene, and fiercely castigates her husband for vacillating. She suggests that if he does not carry out the murder, that he will be a "coward" in his "own esteem," and challenges him by questioning his courage:
Art thou afeard
To be the same in thine own act and valor
As thou art in desire?
This is one of the most intense scenes in an almost unrelentingly intense play, and having questioned her husband's courage, Lady Macbeth then proceeds to challenge Macbeth's masculine honor. Macbeth has apparently sworn to fulfill his destiny by murdering Duncan, and Lady Macbeth says she would commit even the most unthinkable deed before violating such an oath:
I have given suck, and know
How tender ’tis to love the babe that milks me:
I would, while it was smiling in my face,
Have pluck'd my nipple from his boneless gums,
And dash'd the brains out, had I so sworn as you
Have done to this.
So in this confrontation, Lady Macbeth goads her husband into the murder. After it is done, she accuses him of being "infirm of purpose," and even handles the bloody daggers themselves, smearing Duncan's blood on the faces of his two guards. Throughout the first two acts, she aggressively acts to steel her husband against the psychological and moral consequences of his actions. Eventually, though, Macbeth begins to act alone, and is no longer in need of his wife's urging. Moreover, by the final act, before she takes her own life, she is broken and overwhelmed by her own conscience. But her scenes with her husband, especially Act I Scene 7, are some of the most intense and full of pathos of any Shakespeare created.