Adam Smith's account of moral development draws heavily from Joseph Butler's earlier account of resentment and forgiveness in his Sermon VIII, “Upon Resentment,” and Sermon IX, “Upon the Forgiveness of Injuries” (Fifteen Sermons). Smith opens his Theory of the Moral Sentiments with the assertion that human selfishness is limited, as evidenced by our getting some pleasure from seeing the happiness of others. Further, even “the greatest ruffian, the most hardened violator of the laws of society” is susceptible to having some degree of pity or compassion for the misery of others. So, he concludes, some of our sympathies express genuine concern about others, not just ourselves.

Readers might expect Smith next to say more about our positive concern about the happiness of others. Instead, he turns to what he calls our “unsocial passions”—most notably, resentment. Unpleasant in itself, nevertheless resentment seeks a sympathetic audience. However, until we can see why someone is resentful, our reaction to the display of this passion is itself quite negative. In fact, resentment should be viewed as suspect, at least initially. Smith alerts us:

In fact, insofar as it is merely an expression of hatred and anger, he adds, resentment is “the greatest poison to the happiness of a good mind” (TMS, 37).

Nevertheless, says Smith, suitably restrained, resentment can function as “the safeguard of justice and the security of innocence” (TMS, 79). It can be a defensive response that “prompts us to beat off the mischief which is attempted to be done to us, and to retaliate that which is already done; that the offender may be made to repent of his injustice, and that others through fear of the like punishment, may be terrified from being guilty of the like offense” (TMS, 79).

This, Smith believes, is how resentment ought to function when at its moral best.