Galatians 1:1-4:7

Is the law, therefore, opposed to the promises of God? Absolutely not! For if a law had been given that could impart life, then righteousness would certainly have come by the law. But Scripture has locked up everything under the control of sin, so that what was promised, being given through faith in Jesus Christ, might be given to those who believe. (Galatians 3:21-22)

One effect of the legal code found in the Bible is to consign to sin all human efforts to make ourselves righteous.  God is the one who makes us humans righteous. At least two things happen when we by our own efforts try to achieve righteousness: We fail at becoming righteous, and we sin against God. Sin is rebellion against God and God's way of doing things.

But if by faith in Jesus Christ we receive what God promised beforehand, then we have not sinned. Indeed, we have acted in obedience to God. We are included among the righteous before God, thanks to person and work of Jesus Christ. And we begin to be made righteous by the power of God's indwelling Holy Spirit.