Note 8 at 1Co 5:10: Paul was writing about a common biblical theme, separation from ungodliness. However, Paul made a very important point that many people miss when preaching separation. He said that our separation from errant believers must be stricter than from nonbelievers. In other words, we can tolerate some things from unbelievers that we should not tolerate from those who profess to be born again.

It all comes down to a matter of who is affecting whom. If we are in a position where we can change the ungodliness around us, we should seize the opportunity even as Jesus and Paul did (e.g., Mt 9:9-11 and 11:19) and share the love of God with a dying world. To be the salt of the world, we have to get out of the salt shaker. However, we should never allow ourselves to be in a position where we are the ones who are being changed (see note 3 at Ac 19:9).

In a church situation, we should first utilize the disciplinary steps set forth by Jesus (Mt 18:15-17), but if that doesn't work, we should purge out the sin before it infects others (see note 5 at Mt 18:17). Casual contact with the world is less damaging than communion with a brother or sister who is in rebellion to God.