Here are a few great thoughts from the apostle Paul from his letter to the Galatians, with thanks to Eugene Peterson and his The Message translation …
"We Jews know that we have no advantage of birth over "non-Jewish sinners." We know very well that we are not set right with God by rule-keeping but only through personal faith in Jesus Christ. How do we know? We tried it — and we had the best system of rules the world has ever seen! Convinced that no human being can please God by self-improvement, we believed in Jesus as the Messiah so that we might be set right before God by trusting in the Messiah, not by trying to be good.
Have some of you noticed that we are not yet perfect? (No great surprise, right?) And are you ready to make the accusation that since people like me, who go through Christ in order to get things right with God, aren't perfectly virtuous, Christ must therefore be an accessory to sin? The accusation is frivolous. If I was "trying to be good," I would be rebuilding the same old barn that I tore down. I would be acting as a charlatan.
What actually took place is this: I tried keeping rules and working my head off to please God, and it didn't work. So I quit being a "law man" so that I could be God's man. Christ's life showed me how, and enabled me to do it. I identified myself completely with him. Indeed, I have been crucified with Christ. My ego is no longer central. It is no longer important that I appear righteous before you or have your good opinion, and I am no longer driven to impress God. Christ lives in me. The life you see me living is not "mine," but it is lived by faith in the Son of God, who loved me and gave himself for me. I am not going to go back on that.
Is it not clear to you that to go back to that old rule-keeping, peer-pleasing religion would be an abandonment of everything personal and free in my relationship with God? I refuse to do that, to repudiate God's grace. If a living relationship with God could come by rule-keeping, then Christ died unnecessarily."
[Galatians 2:15-21. Message Bible]