A pretty stunning passage from philosopher Charles Taylor’s A Secular Age describing the 19th century slide that Christianity took into moralism, and how the natural endpoint of that slide is unbelief, ht KW:
Perhaps the most important for our purposes was the protest against a narrowing of the ends of life to a code of conduct: This ethic of discipline, in both believing and unbelieving variants, was a moralism. It put discipline, self-control, the achieving of a high moral standard as the supreme goal. This tended to be true even of the Evangelical modes, which had after all started in the previous century as a reaction against narrow moralism, for instance in the emotionally liberating preaching of Wesley. Like all moralisms, it could come to seem too thin, too dry, concerned so exclusively with behaviour, discipline, control, that it left no space for some great elan or purpose which would transform our lives and take us out of the narrow focus on control. The obsession with getting myself to act right seems to leave no place for some overwhelmingly important goal or fulfillment, which is the one which gives point to my existence.