But does that mean the pastor should preach to his congregation as if they are "horrible sinners"? Should the truth of the universal corruption of mankind lead the preacher to address the members of his flock as though they are ruled by deliberate sin?
C. F. W. Walther would say, "No way!" Thesis XVIII of Walther's Law and Gospel says,
You are not rightly distinguishing Law and Gospel in the Word of God if you describe the universal corruption of mankind so as to create the impression that even true believers are still under the spell of ruling sins and sin deliberately (C. F. W. Walther, Law and Gospel: How to Read and Apply the Bible, p. 355).Walther explains what he means by looking at various Bible passages. Here's what he says when he considers Matthew 3:17 and Romans 6:14:
When we speak of "horrible" sinners, we must not refer to Christians, in whom we find weaknesses, which are covered with the righteousness of Christ, yet also good deeds, which God does through them and which are pleasing to Him. All baptized Christians may apply to themselves the declaration of God: "This is My beloved Son, with whom I am well pleased." [Matt. 3:17]Sounds like some sanctified fine-tuning and honing of our preaching is always in order!
Romans 6:14: "For sin will have no dominion over you, since you are not under law but under grace." [Paul] is actually saying not only that sin should not dominate Christians but also that sin is no able to dominate Christians. In fact, it is absolutely impossible for a person who is in a state of grace to be ruled by sin. When a pilgrim traveling on a lonely road is attacked by a robber, the pilgrim will escape from the robber at the first opportunity because he does not want to be overcome and killed. Christians are pilgrims in this world and are on their way to heaven. Like a highway robber, the devil assaults them, and they collapse before him because of their weakness--not because they want to collapse. When true Christians collapse, they are forgiven because they turn to God in daily and tearful repentance--or at least with heartfelt sighs, begging for pardon. But if a person allows sin to rule him, that is a sure sign that he is not a Christian but a hypocrite--no matter how pious he pretends to be (C. F. W. Walther, Law and Gospel: How to Read and Apply the Bible, p. 357, emphasis original).