There was a report of sexual immorality in the church at Corinth. In their pride, the church refused to confront it. Paul told them they must remove from the church the man who was committing this sin. Evidently, it was ongoing, and he refused to repent. Paul likened removing him from the church to the Israelites removing leaven when they observed the Feast of Unleavened Bread. Paul’s concern was that as leaven permeates a lump of dough, sin would permeate the church if they did not remove it.