Faith
Paul is writing to Christians who have become confused about the role of faith. Those who had been raised as Jews spent their lives obeying the rules found in the Old Testament. It was hard for them to understand being made righteous by faith. Paul makes it clear that rules don’t make people good, they make people bad. Without rules, bad doesn’t exist.
It’s a strange way of looking at rules, but we can’t deny the logic. The rules point out our flaws and remind us of the need for forgiveness. Recognizing the need for forgiveness, we should turn to Christ in faith. Have you done that, or are you relying on rule-following?