Verses 1-10: Paul's Jerusalem Visit and Apostolic Fellowship. Paul recounts his trip to Jerusalem with Barnabas and Titus, emphasizing the revelation that guided him and the acceptance he received from the church leaders, including James, Cephas, and John. They affirm his mission to the Gentiles and encourage him to remember the poor.
Verses 11-14: The Confrontation with Peter. Paul describes a public rebuke of Peter in Antioch for withdrawing from Gentile believers out of fear of Jewish Christians, exposing the inconsistency between Peter's actions and the truth of the gospel.
Verses 15-21: Justification by Faith, Not Law. Paul explains the theological foundation for his confrontation, teaching that no one is justified by the works of the law but by faith in Jesus Christ. He emphasizes the believer's new life in Christ and warns against nullifying God's grace.