In Act 3, scene 1, of Shakespeare’s Macbeth, Macbeth meets with the two murderers who are to kill Banquo and his son, and Macbeth hints that if they do not do so, they are not really men. The first murderer insists that they are indeed men in response to Macbeth’s apparent hint that Banquo and son must be gotten rid of and his implied question of why the murderers haven't yet completed their task.
Macbeth responds that they fall under the catalogue or species of men but he adds the metaphor that all kinds of creatures go under the catalogue of dog, too, including both hounds and mongrels. He clearly implies that the murderers are the mongrels and not the hounds. If they do not carry out the task set before them, the murderers are not really men at all. Banquo is Macbeth’s enemy, and therefore he must be the murderers’ enemy as well, and thus they are to get rid of him and his son. Macbeth wants no one to stand in the way of his kingship—least of all Banquo’s heir, whom the witches have prophesied would one day take the throne.
Macbeth takes a page out of his wife’s book when he speaks to the murderers. Earlier, when Macbeth hesitates about killing Duncan, Lady Macbeth questions her husband’s manhood and indicates that if he does not take this opportunity and seize the throne by any means possible, then he really is no man at all. Macbeth seems to have absorbed this message.
These incidents tell us something about the concept of manhood and honor in Shakespeare’s day. It was an insult to have one’s manhood questioned or to be thought a coward, and many men would go to any lengths to avoid such ridicule—even if that meant engaging in morally compromising activities.