Romans 5 is pretty popular. We hear it regularly in worship. In fact, we heard most of last Sunday's first reading just a few months ago in Lent. However, we never get to hear the last two verses of Romans 5:
20 But law came in, with the result that the trespass multiplied; but where sin increased, grace abounded all the more, 21so that, just as sin exercised dominion in death, so grace might also exercise dominion through justification leading to eternal life through Jesus Christ our Lord.
These few verses are important. They remind us that the law actually increases sin. When we are told not to do something, we actually desire to do it all the more. Trespasses multiply under the law. But just as sin and death exercise dominion over so, grace abounds all the more under them. Now we live under the dominion of grace because of Jesus' work for us, making us God's own people, that we might belong to God forever.