Heidelberg Catechism: Lord's Day 30, 1 Corinthians 5:9–11, 1 Corinthians 10:14–22, 1 Corinthians 11:23–34
1. The command to all believers: do this!
2. The warning to all believers: but not if you are doing this!
3. The exclusion of some believers: because they show themselves to be this!