PAUL OPPOSED PETER FACE TO FACE.
Antioch in Syria ( distinguished from Antioch in Pisidia) was a major trade center in the ancient world. Heavily populated by Greeks, it eventually became a strong Christian center. In Antioch the believers were first called Christians (Acts 11,26). Antioch in Syria became the headquarters for the Gentile Church and was Paul's base of operations. The Judaizers ( circumcision group) accused Paul of watering down the gospel to make it easier for Gentiles to accept, while Paul accused the Judaizers of nullifying the truth of the Gospel by adding conditions to it. The issue was the basis of salvation - is salvation through Christ alone, or does it come through Christ and adherence to the law? The argument came to a climax when Peter, Paul, the Judaizers, and some Gentile Christians all gathered together in Antioch to share a meal ( Galatians 2,11). Peter probably thought that by staying away from the Gentiles, he was promoting harmony - he did not want to offend James and the Jewish Christians. James had a very prominent position and presided over the Jerusalem council (Acts 15). But Paul charged that Peter's action violated the Gospel. By joining the Judaizers, Peter implicitly was supporting their claim that Christ was not sufficient for salvation.
Although Peter was a leader of the Church, he was acting like a hypocrite; he knew better, yet he was driven by fear of what James and the others would think. Paul opposed Peter face to face, by a direct approach. There is no place for backstabbing in the body of Christ. (Zondervan).