yet we know that a person is not justified by works of the law but through faith in Jesus Christ, so we also have believed in Christ Jesus, in order to be justified by faith in Christ and not by works of the law, because by works of the law no one will be justified.
The battle being waged in the book of Galatians is a battle for the truth of the gospel. Paul makes it clear that no person can be justified by doing anything "holy". Even if it were possible to keep the works of the OT law, such actions would not be sufficient. Christ Jesus has died for us and we must put our trust in Him alone for our souls to be right before God. There is no other way.
Paul's ministry was beset with these battles with those who rejected this gospel. It was more "religious" for these Judaizers to insist that Gentiles put themselves in relationship with the law that required something extra. It is Jesus plus something. And that kind of gospel is not the true gospel. Our salvation is solely found in the redemptive work of Christ. We cannot perform any kind of self-righteous act to save ourselves.
Paul knew this. He lived it. As a Jew himself, he was compelled to trust Christ alone. His conversion to this gospel was dramatic, because he fought so hard to stamp it out. But when Jesus called him, Paul was convinced He was Lord, and from that moment on, being "zealous for the law" ceased to be the drive of Paul's heart. He became a man who was passionate for the gospel that saved him.
We must always be on the guard against any theology, any addendum to the truth that insists that the real gospel is "Jesus plus something". The good news is that believing Christ as Lord, accepting His atoning work on the cross, and trusting Him alone for eternal salvation and saving life is what gives us peace with the Father. There is no other gospel. We are saved by faith in Christ.
- Prepare your minds for action.
1 Peter 1:13