But when Peter came to Antioch, I had to oppose him publicly, speaking strongly against what he was doing, for it was very wrong.
When he first arrived, he ate with the Gentile Christians, who don't bother with circumcision. But afterward, when some Jewish friends of James came, Peter wouldn't eat with the Gentiles anymore because he was afraid of what these legalists would say.
Then the other Jewish Christians followed Peter's hypocrisy, and even Barnabas was influenced to join them in their hypocrisy.
When I saw that they were not following the truth of the Good News, I said to Peter in front of all the others, "Since you, a Jew by birth, have discarded the Jewish laws and are living like a Gentile, why are you trying to make these Gentiles obey the Jewish laws you abandoned?
You and I are Jews by birth, not 'sinners' like the Gentiles.
And yet we Jewish Christians know that we become right with God, not by doing what the law commands, but by faith in Jesus Christ. So we have believed in Christ Jesus, that we might be accepted by God because of our faith in Christ -- and not because we have obeyed the law. For no one will ever be saved by obeying the law."
References for Galatians 2:16
But what if we seek to be made right with God through faith in Christ and then find out that we are still sinners? Has Christ led us into sin? Of course not!
Rather, I make myself guilty if I rebuild the old system I already tore down.
For when I tried to keep the law, I realized I could never earn God's approval. So I died to the law so that I might live for God. I have been crucified with Christ.
I myself no longer live, but Christ lives in me. So I live my life in this earthly body by trusting in the Son of God, who loved me and gave himself for me.
I am not one of those who treats the grace of God as meaningless. For if we could be saved by keeping the law, then there was no need for Christ to die.