Adam Smith's key insight is that both parties to an exchange can benefit and that, so long as cooperation is strictly voluntary, no exchange can take place unless both parties do benefit.
Adam Smith's vision, like with Ludwig von Mises, sees man as a victor over instinct and impulse (whereas Karl Marx and Freud takes man as a victim of oppression).

Adam Smith is an egalitarian who believed in equality of outcome, not opportunity. He is an enlightenment figure, pre-capitalist. He says, suppose in England, one landowner got most of the land and other people would have nothing to live on. He says it wouldn't matter much, because the rich land owner, by virtue of his sympathy for other people would distribute resources among them, so that by an invisible hand, we would end up with a pretty egalitarian society. That is his conception of human nature.
Adam Smith is a thinker in whose vision, individuals and groups of individuals are the proper players in the game of life with the ideal State functioning as umpire rather than player, much less director.