Discipline within the church
Paul carefully explains to the church in Corinth how important it is to go into the world and convert the immoral, greedy, swindlers & idolaters. But not to associate with those who call themselves Christians and still continue to sin. Expel them from the church!
Even today this happens within our churches and it is very difficult for the elders to take action in love to expel the wicked person (who really needs the Lord) from the church. We need to pray for the elders who care for our flocks so that the church would remain pure and holy.