Paul is digging down into specifics with what has been going wrong at church. He mentions sexual immorality that even the pagans don’t do, a man openly sleeping with his father’s wife. Two points of contrast to the interaction with Jesus and the woman caught in adultery (John 8), this is a man with agency being held accountable, and his punishment is expulsion not death. Paul tells the community to not allow him to stay. He says it in the strongest language, “deliver him to Satan.”

The reason for this removal is so that this affair doesn’t infect the whole fellowship of believers like “bad leavening” that Christ warned us of. When the sourdough starter gets fuzzy, green spots in it, you have to toss it and start from scratch. 

Paul talks about Christ being the Passover lamb. He is tying his leavening metaphor the story in Exodus where the Israelites made yeast-free bread in anticipation of fleeing slavery— they didn’t have time to let bread rise. The event was called Passover because the Angel of Death passed over any house that had the blood of the sacrificed lamb over the door. The Jews then and now remember Passover by eating unleavened bread. 

Paul reminds the church to not associate with the immoral, not judging the people of the world who don’t know better, but those who do. Along with sexual sins, he includes those who call themselves a brother (what the Church referred to as believers at the time) that continued to be an idolator, drunkard, reviler (slander or angry outbursts) or swindler. Part of becoming a follower of Christ is to leave the lifestyle of sin that would bring down the family of God. 

Many churches today still struggle to keep their own leaders accountable. The world knows that the church preaches morality, but doesn’t maintain the standards it holds for others. Paul is leaving God to judge outsiders, but calling insiders to accountability.