What did the Corinthian church's confronting of the offender do for the whole congregation?
Confronting the offender enhanced the whole congregation. It showed them that God could move into even a vile situation, clear the deck, and restore everyone once again to fellowship with the Holy God. The result reverberated throughout the congregation, strengthening the members as they witnessed God's cleansing and restorative work among them.
Les explains that when the Corinthian church took the gentleman aside and laid out God's view of his actions and the reverberations it was having in the pagan city of Corinth, the news traveled. What did it do for the whole congregation? It enhanced every one of them, because they could see that God could move into a situation even as vile as this one, clear the deck, and make everyone once again in fellowship with the Holy God. It just reverberated throughout the congregation. Paul also wrote that he did it not merely for the cause of the one who had done the wrong or the one who had suffered wrong, but that his care for them in the sight of God might appear to them. If Paul had glossed over it as the congregation was doing, it would have said he was no better than the rest of them, looking at it as they did and treating it as not all that bad.
For behold this selfsame thing, that ye sorrowed after a godly sort, what carefulness it wrought in you, yea, what clearing of yourselves, yea, what indignation, yea, what fear, yea, what vehement desire, yea, what zeal, yea, what revenge! In all things ye have approved yourselves to be clear in this matter.