Galatians 2:13-16

And the rest of the Jews dissembled likewise with him; insomuch that even Barnabas was carried away with their dissimulation. But when I saw that they walked not uprightly according to the truth of the gospel, I said unto Cephas before them all, If thou, being a Jew, livest as do the Gentiles, and not as do the Jews, how compellest thou the Gentiles to live as do the Jews? 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.