In Galatians 2:11-14, Paul fights for the truth of the gospel as he points out a critical error that Peter made with regards the Gentile believers. But before we can truly understand what’s going on in Galatians, we must see the background in Acts 10 & 11. There we see Peter received a vision from God that the Jewish food laws of the Old Covenant, and the separation from Gentiles were now over! Of course, Peter needed some time to understand this. Eventually he realized that God did it to make a way for all peoples on earth to enter the family of God through Jesus Christ.
Having seen this vision, then, why would he take a step backwards in Antioch? (Gal. 2:11-12) How often have we ourselves seen something from God, walked in it for some time, and later to live as though we’d never seen it? Thankfully we have a God who is for our progress & growth in the faith he has called us too. He restores those who take a step backwards. He did this for Peter, and we see evidence of this in Acts 15:7b-10. There, Peter speaks clearly about how God has opened the way for the Gentiles in his family.