Galatians 2:15-16, 21

We being Jews by nature, and not sinners of the Gentiles, yet knowing that a man is not justified by the works of the law but through faith in Jesus Christ, even we believed on Christ Jesus, that we might be justified by faith in Christ, and not by the works of the law: because by the works of the law shall no flesh be justified.

I do not make void the grace of God: for if righteousness is through the law, then Christ died for nought.