How does Paul defend Christian freedom and justification by faith against demands for Mosaic legal observance?

Paul recounts his journey to Jerusalem fourteen years later with Barnabas and Titus, undertaken in response to revelation to present before church leaders the gospel he proclaimed among the nations, verifying that his labors were not in vain. Although Titus was a Gentile, the apostolic leadership did not compel him to undergo circumcision, resisting covert infiltrators who crept into the community to spy on Christian freedom and force the faithful into legal servitude. Refusing to surrender their evangelical freedom for a single hour, the missionaries preserved the truth of the gospel intact. Acknowledged leaders contributed nothing new to Paul's preaching, recognizing instead that evangelization of the Gentiles had been committed to him just as the mission to the Jewish people was assigned to Peter, with God energizing both ministries. Challoner's commentary explains that the gospel of the uncircumcision refers to the Gentiles, establishing Paul as an extraordinary apostle while Peter retained universal pastoral oversight over the whole flock alongside particular care for the Jews. Perceiving this divine grace, James, Cephas, and John extended the right hand of fellowship to Paul and Barnabas, agreeing that the two teams would minister respectively to Gentiles and Jews, requesting only that they remember the needy, a duty Paul was diligent to fulfill.

The harmony was tested at Antioch, where Paul openly confronted Cephas face to face because his public conduct invited censure. Prior to the arrival of some men who came from James, Peter shared meals freely with Gentile converts; however, once they appeared, he withdrew and segregated himself out of apprehension toward the circumcision faction. This retreat led other Jewish believers into pretense, sweeping even Barnabas into identical dissimulation. Seeing that their actions compromised evangelical integrity, Paul challenged Cephas before the entire gathering, questioning how he, though born a Jew yet living like a Gentile, could consistently coerce Gentile converts into adopting Jewish customs. Challoner notes that Peter's fault was pastoral imprudence in withdrawing to avoid offending Jewish converts, which risked misleading Gentiles into thinking Mosaic rites were obligatory; Paul's respectful public admonition did not contradict Peter's supreme authority, since an inferior may dutifully caution a superior when essential liberty is endangered.

Paul deepens this rebuke into a foundational theological argument, asserting that although he and his peers were Jews by lineage rather than Gentile sinners, they recognized that no human being is justified through legal works, but through faith in Jesus Christ. Jewish believers therefore placed their trust in Christ Jesus to attain righteousness through faith rather than ceremonial deeds, because by the works of the law no human being can achieve justification. Seeking righteousness in Christ does not make Christ a promoter of sin if believers are still recognized as sinners; rather, reconstructing discarded legal requirements makes the builder an authentic transgressor.

Through the operation of the law, Paul died to legal bondage so that he might live exclusively unto God, having been nailed to the cross alongside Christ. He declares that his current life is no longer his own, because Christ lives within him, and his earthly existence is sustained through faith in the Son of God, who loved him and gave Himself up for his salvation. Refusing to nullify divine grace, Paul concludes that if righteousness could be attained through legal observance, then Christ died without purpose.