But when Peter came to Antioch, I resisted him face to face, because he was condemning. For before certain of James' people came, he ate with the Gentiles; but after they came, he withdrew and withdrew, because he was afraid of those of the circumcision.
And the other Jews also took part in their pretence, so that even Barnabas was drawn away by their hypocrisy. But when I saw that they did not walk uprightly according to the truth of the gospel, I said to Peter before them all, "If you, being a Jew, live like the Gentiles and not as a Jew, why do you compel the Gentiles to become Jews? We, Jews by birth, and not sinners from among the Gentiles, knowing that a man is not justified by the works of the law, but by the faith of Jesus Christ, even we have believed in Jesus Christ, that we might be justified by the faith of Christ, and not by the works of the law; for by the works of the law shall no flesh be justified.
And if, seeking to be justified in Christ, we also are found sinners, is Christ therefore a minister of sin? Not at all. For if I build again the things which I have destroyed, I am a transgressor.
For I through the law am dead to the law, that I might live unto God. I am crucified with Christ: nevertheless I live; yet not I, but Christ liveth in me: and the life which I now live in the flesh I live by the faith of the Son of God, who loved me, and gave himself for me. I do not cast away the grace of God: for if righteousness were of the law, then Christ died in vain.
Galatians 2: 11-21