King James Bible
"But when I saw that they walked not uprightly according to the truth of the gospel, I said unto Peter before them all, If thou, being a Jew, livest after the manner of Gentiles, and not as do the Jews, why compellest thou the Gentiles to live as do the Jews?"
Paul observes Peter and others acting inconsistently with the gospel's core message of salvation by grace alone. Their behavior contradicted the truth that Jew and Gentile are equal in Christ, prompting Paul's public confrontation. Paul confronts Peter publicly rather than privately because the offense was public and affected the entire church. This bold action demonstrates the gravity of the issue and Paul's apostolic authority to correct even prominent leaders. Paul exposes Peter's hypocrisy: he had been eating with Gentiles and ignoring Jewish dietary laws, acknowledging their freedom in Christ. Peter's own actions proved he knew Jewish customs were not binding for salvation. The pointed question highlights the absurdity of Peter's withdrawal from Gentile fellowship after certain Jews arrived. By his actions, Peter was implicitly forcing Gentiles to adopt Jewish practices to gain full acceptance, undermining the gospel of justification by faith.