In act 1, scene 7, Macbeth tells his wife that he is no longer willing to murder King Duncan. Lady Macbeth, determined to become Queen, sets about changing her husband's mind by belittling his masculinity. She mockingly asks her husband if he is "afeard" and if he is prepared to "live a coward in [his] own esteem." Macbeth, initially, is resolute, and insists that he "dare[s] do all that may become a man," and that "who dares do more is none." For Macbeth, masculinity is characterized not just by action, but also by morality and self-discipline.

Lady Macbeth, however, sensing a vulnerability, keeps on attacking her husband's masculinity. She tells Macbeth that when he was prepared to kill King Duncan, then he "were a man," the implication being that he is no longer a man now that he has changed his mind. Lady Macbeth also tells her husband that if he were to become king he would be "so much more the man," implying that he can not be fully a man until he has fulfilled the prophecy told to him by the three witches and become king.

After this continued barrage from his wife, Macbeth's resolution weakens. He says that he will murder the king after all, and that he is "settled" upon this course of action. The implication one might draw from this exchange between Lady Macbeth and her husband is that the latter's insecurities about his own gender, specifically his masculinity, are so profound as to lead him along a path that leads ultimately to regicide.