The Theory of Moral Sentiments was not presented as a set of rules or instructions about how to behave or how to think. Rather, Smith speculated on the way in which people formed their ideas on these subjects. His idea that we should assess our thoughts and feelings as the impartial spectator would see them parallels the biblical advice to judge other people as we would judge ourselves. He cites the Decalogue (the Ten Commandments), but only in reference to honoring parents.

Smith did not make many references to overtly Christian writers; there are many more references to Greek and Roman authorities. A rare exception is a section dealing with the “casuistry” of such Roman Catholic authorities as Saint Thomas Aquinas. The tone is not very respectful: The practice of confession is associated with “superstition.” Smith’s illustration of rules of casuistry asks, Suppose a robber extracts from his victim a promise to pay him a large sum of money on his release. Is the victim morally bound to pay it?

Jesus’ name never appears, but Smith affirms that “to love our neighbor as we love ourselves is the great law of Christianity,” adding “so it is the great precept of nature to love ourselves only as we love our neighbor.” A rather inconclusive passage examines the impulses of benevolence in relation to the commandment to love God and one’s neighbor. A more sympathetic rendering of the same theme refers to Greek philosophers as well as “many ancient fathers of the Christian church.” Smith is skeptical about the contribution to happiness from more goods, but he articulates the important view that the quest for material wealth can lead to productive actions and (unintended) benefits for the entire society.

Smith’s own sentiments appear to differ from mainstream Christian doctrine at many points. A notable example is his opinion that “the futile mortifications of a monastery” appear far less worthy than “the ennobling hardships and hazards of war.” Smith assumes that it is proper for our benevolence to be primarily directed toward our inner circle of family and friends. He commends the sentiments of universal benevolence but suggests that is God’s concern. Mere mortals should direct their concern toward persons whose needs and conditions they know at firsthand. We find no counterpart of Christ’s command that we love our enemies. At the same time, Smith was a consistent internationalist, condemning attitudes of rivalry and antagonism between nations. This was to become a major theme of The Wealth of Nations, in which Smith vigorously defended free trade and condemned the idea that another nation’s improvement was somehow one’s own loss.

Some critics have classed Smith as a Deist for references that emphasize the wisdom and benevolence of the Creator and imply that he saw God as the “divine watchmaker” who, after Creation, now sits back and lets the system operate spontaneously according to the natural laws he set in place. Smith refers approvingly tothe idea of that divine Being, whose benevolence and wisdom have, from all eternity, contrived and conducted the immense machine of the universe, so as at all times to produce the greatest possible quantity of happiness. . . .

Finally, Smith examined the promises of life after death somewhat skeptically, noting that the greatest rewards were promised for acts and attitudes of faith and devotion in a manner often opposed to our moral sentiments.