We sin against Christ and we misrepresent the Gospel when we suggest to sinners that what God demands of them is moral improvement in accordance with the Law. Moralism makes sense to sinners, for it is but an expansion of what we have been taught from our earliest days. But moralism is not the Gospel, and it will not save. The only gospel that saves is the Gospel of Christ. As Paul reminded the Galatians, "But when the fullness of the time came, God sent forth His Son, born of a woman, born under the Law, so that He might redeem those who were under the Law, that we might receive the adoption as sons." [Gal. 4:4-5]
...The deadly danger of moralism has been a constant temptation to the church and an ever-convenient substitute for the Gospel. Clearly, millions of our neighbors believe that moralism is our message. Nothing less than the boldest preaching of the Gospel will suffice to correct this impression and to lead sinners to salvation in Christ.