Of course. And of course not. The sermon is that part of the service where God’s Word exposes our failures, and proclaims Christ’s provision. The end is not the sin, but neither can the sin be ignored. The pastor does not preach simply to tell the congregation, “Stop it. Try harder. This is the right way to go.” Rather he preaches to tell the congregation, “Stop trying harder. Jesus already went this way.” That is, he wants us to face our sins, give thanks for the forgiveness of our sins, and in gratitude seek to follow the royal law of love. As such pastors do indeed preach sin. The notion that a pastor should hide the sins of the flock from the flock, so as not to offend, to keep them from leaving the church is pure folly. No church has enough musical skill, no pastor enough entertaining style, no coffee shop enough tasty coffee to keep the crowds coming. What the church has are the words of eternal life, which begin with “Repent,” and end with “and believe the gospel.”
Even in less seeker-friendly services though we can find the same problem. Here the pastor is willing to preach against sin, but against the sins of those who are absent. He may fuss about the bad theology, or the bad strategy of the church down the street. Or he may thunder against the sins of the world. But it is the sheep of his fold that need to know and repent from their sins. He is not called to prophecy against Nineveh safe in the streets of Jerusalem.
In what sense then is it wrong to preach against the sins of the congregation? Well, the pastor is not called when he steps into the pulpit to deliver a sermon inspired by Mr. Jones’ inability to make it to church on time, or Mrs. Brown’s propensity to spread gossip. Now it may well be that someone needs to talk to Mr. Jones, or Mrs. Brown, but the sermon is not the time for that. A pastor ought not take up the time he has been given to open up the text of God’s Word in order to do private discipleship in public. He does not abuse his opportunity to put someone in his place.
How do we avoid both of these failures? The preacher should preach to his own sins. It is likely that this will include the sins of his own congregation. While we all sin spectacularly, we likewise mostly sin the same. The sins of the congregation likely don’t exclude the preacher. When the pastor preaches against his own sins he can address where “we” go wrong, and are in need of grace and repentance, rather than a situation where he preaches against where “you” go wrong.
Preaching ought to convict. Otherwise it’s just wasted time. It ought, however, to also provide the solution to our guilt, in extolling the provision in Christ. May all preachers decrease, and the One they preach, may He increase.