In our own context, one of the most seductive false gospels is moralism. This false gospel can take many forms and can emerge from any number of political and cultural impulses. Nevertheless, the basic structure of moralism comes down to this -the belief that the Gospel can be reduced to improvements in behavior.
The seduction of moralism is the essence of its power. We are so easily seduced into believing that we actually can gain all the approval we need by our behavior. Of course, in order to participate in this seduction, we must negotiate a moral code that defines acceptable behavior with innumerable loopholes. Most moralists would not claim to be without sin, but merely beyond scandal. That is considered sufficient.
Moralists can be categorized as both liberal and conservative. In each case, a specific set of moral concerns frames the moral expectation. As a generalization, it is often true that liberals focus on a set of moral expectations related to social ethics while conservatives tend to focus on personal ethics. The essence of moralism is apparent in both — the belief that we can achieve righteousness by means of proper behavior.
Read the rest of Dr. Mohler's article here.