If we look down to it to submerge more deeper, we find further a wider horizon of understanding which the Galatians succumbed to the Jewish practices as the old tradition may require it. The new testament was not yet completed to gain more access to divine doctrinal foundation for even Peter slid to the point of erroneous understanding which resulted to unethical application.
The confrontation of Paul against Peter, that he stood him by the face, brought Peter to concede because he was guilty of doing so. Peter grasped the concrete foundation of grace for many reasons: 1.) No man is justified by the works of the law - Gal. 2:16 KJV. 2.) Man is save by grace through faith and not of works - Eph. 2:8-9 KJV. 3.) The Jews by nature (believers in Christ) are not sinner’s to the Gentiles - Gal. 2:15. 4.) If righteousness come by the law, then Christ is dead in vain - Gal. 2:21 KJV.
The confrontation of Paul and Peter is not just by circumstance in some occasion. Paul has knowledge about it because it is a regular meeting of Peter with the gentiles (probably some are Galatians and rest of the gentiles). I should say, maybe a common fellowship. Peter might have some disciples with him during that occasion as the servings of food is Jewish delicacy. This is one of Paul’s irritating gesture to confront Peter aside from any other else.
But the worst that Paul’s reprimanding action is that, when he directly interrogated Peter why he did compelled the Gentiles to live as do the Jews.
I may guess some points to discuss in this juncture why Paul indignantly confronted Peter in this undesirable occasion. One is the ironic condition which Peter employed as regard to the law. In Romans 10:4 states, that Christ is the end of the law. Before the Calvary event, the law is still binding in the Jews tradition, of course, exception to the gentiles. In the dispensation of grace, Christ is the end of the law. And why should the gentiles (converted to christian) must have to live with that standard of the law?
Paul must have a strong ground to defend and to prevent it to happen. Gentiles are not Jews and have not the right even to be. But because of Christ, Gentiles were converted to share the abundance of GRACE (God’s Riches At Christ Expense - 2 Cor. 8:9 KJV) and not to become Jews by practice.
Paul is silent to this point behind for he knew then that gentiles to become Jews (while believing in Christ) is a blasphemy - Revelation 2:9; 3:9 KJV…