The dialogue of the first part of the scene reveals that Macbeth has met the murderers before. Both then and now, he must convince them to work on his behalf. Whether true or not (we have no evidence), he kindles, or re-kindles, in them, a hatred of Banquo: "Know that it was he . . . ," "This I made good to you in our last conference," "Do you find your patience so predominant in your nature that you can let this go?" The tone of these quotations is more than simply interrogative; Macbeth must ensure that the men are not persuaded by the slightest moral scruple, the slightest sympathy for Banquo, to betray the plan. Such a reaction would be entirely natural and human, but that humanity is precisely what Macbeth cannot now allow. Therefore, when the First Murderer replies, "We are men, my liege," Macbeth cuts off his speech and, in a sequence of powerful metaphors, reduces the humanity of these murderers to the level of beasts: "Ay, in the catalogue ye go for men, / As hounds and greyhounds, mongrels, spaniels, curs / . . . and demi-wolves are clept [called] / All by the name of dogs" (93–96).
Although Macbeth flatters the Murderers by suggesting that the business of Banquo's murder will elevate them above the common rank, his ironic tone reveals that he thinks of them as little more than beasts. Doubly ironic, then, is that this entire speech is admission to himself of his own inhumanity and imperfection: Macbeth himself is acting like a "demi-wolf." The lines are triply ironic when we see that indeed the murderers are, themselves, imperfect in carrying out his instructions for the "perfect" crime.
