What is the righteousness of God in relation to the law?
The righteousness of God is without the law. It is not obtained by deeds or keeping the law, since no flesh is justified by law. The law only gives the knowledge or awareness of sin and can only condemn; it has no power to help. Human righteousness is like filthy rags, but God's righteousness is apart from law.
Les explains in the review of verse 20 going into verse 21 that by the deeds or keeping of the law shall no flesh be justified in His sight, for by the law is the knowledge or awareness of sin. That law, connected to old Adam, could do nothing but condemn; it had no power even to help the Jew be a law keeper. All it could do was point the finger and say you're guilty. But then comes the flip side: the righteousness of God, not human righteousness—which is like filthy rags—is without the law. Les emphasizes you cannot get it any plainer than that.