Paul treads a narrow path through the relationships between the law, those who were under the law, and those who were not. These verses are at the heart of what Paul is getting at:
21 But now apart from the law the righteousness of God (although it is attested by the law and the prophets) has been disclosed— 22 namely, the righteousness of God through the faithfulness of Jesus Christ for all who believe.
Romans 3:21, 22
There is much debate over the exact translation of “faithfulness of Jesus Christ”. The NIV opts for the more traditional rendering: “through faith in Jesus Christ.” One thought that reconciles these two views is that Jesus Christ is worthy of our faith because he is faithful. Regardless of our exact understanding of this one phrase, it’s clear that Paul is distinguishing the old understanding of the righteousness of God through the law, with a new understanding of God’s righteousness that is now based on our faith in his faithful son, Jesus.
And the narrow path Paul treads is what is the exact relationship between the old and the new understanding. His conclusion is that for both old and new, people will be justified through faith. And he resolves the apparent contradiction with the law by insisting that this understanding of righteousness through faith actually upholds the law! Imagine that.
30 Since God is one, he will justify the circumcised by faith and the uncircumcised through faith. 31 Do we then nullify the law through faith? Absolutely not! Instead we uphold the law.
