According to J. J. Bütz, The Brother of Jesus, Paul must have written his Epistle to the Galatians before the Jerusalem Council of c. 50 AD. This is because Paul makes no mention of the Jerusalem Decree, sent out by James the Just and the Jerusalem Elders from that Council, acknowledging that gentiles did not need to be circumcized to become Christians (Acts 15:22-29). In that Decree, James the Just explicitly disowns the "circumcision party" that plagued the Galatian congregation and prompted Paul's letter (v. 24). Indeed, after that Decree was issued, Paul would have had no need to write the letter in the first place. Thus, the letter must have been written before c. 50 AD. Yet, it must have been written after Paul's First Missionary Journey (46-48 AD), when Paul first made inroads into Galatia. This means the letter was written from Antioch c. 49 AD when Paul "remained no little time with the disciples" (Acts 14:28). Therefore, Galatians is Paul's earliest extant writing. SCRIPTURAL EVIDENCE: (1) DISSENTION & CIRCUMCISION PARTY — Acts 15:1-2 = Galatians 2:11-14
But some men came down from Judea and were teaching the brothers, "Unless you are circumcised according to the custom of Moses, you cannot be saved." And after Paul and Barnabas had no small dissension and debate with them, Paul and Barnabas and some of the others were appointed to go up to Jerusalem to the apostles and the elders about this question. Acts 15:1-2 But when Cephas came to Antioch, I opposed him to his face, because he stood condemned. For before certain men came from James, he was eating with the Gentiles; but when they came he drew back and separated himself, fearing the circumcision party. And the rest of the Jews acted hypocritically along with him, so that even Barnabas was led astray by their hypocrisy. But when I saw that their conduct was not in step with the truth of the gospel, I said to Cephas before them all, "If you, though a Jew, live like a Gentile and not like a Jew, how can you force the Gentiles to live like Jews?" Galatians 2:11-14
Again, Paul wrote Galatians in c. 49 AD before the "men from James" (Gal 2:11) were unmasked, at the Jerusalem Council in c. 50 AD, as rogues who did not have James' true authority (Acts 15:24).FURTHER IMPLICATIONS: (1) Paul visited the Jerusalem Church after every Missionary Journey: 1st (Gal 2:1), 2nd (Acts 18:22), 3rd (Acts 21) (2) The bitter acrimony between Paul and the Pillars of the Church (James & Peter) was quickly resolved — James said, "our beloved Barnabas and Paul" (Acts 15:25 — 50 AD); cf. Peter "our beloved brother Paul" (2 Peter 3:15 — 67 AD). (3) Thus, Paul did not reject, but instead fully accepted, the authority of James, Peter, and the Jerusalem Church. In turn, the Jerusalem Church fully recognized Paul's ministry. (4) Early Christianity was "bi-cameral" — Jewish Believers in Jesus as Messiah were strictly Law observant (including Paul), while Gentile Christians were only required to follow the Commandments of the Jerusalem Decree. Indeed, James the Just explicitly states this fact (Acts 21:25). (5) Paul's return to Jerusalem in 48 AD after his First Missionary Journey (46-48 AD) happened "fourteen years" after his conversion experience (Gal 2:1). Thus, Paul met the risen Jesus on the road to Damascus in 34 AD. Further, Paul lived in Damascus for the next "three years", from 34-37 AD (Gal 1:18). Paul then fled from the city due to the persecution of the governor of King Aretas (2 Cor 11:32) prompted by the petitions of (influential) Jews to the same (Acts 9:23). This must have been in 37 AD — consistent with the fact that Aretas only had authority over Damascus from 37-40 AD under Emperor Caligula, after the death of Tiberius (Mar. 37 AD), and before Aretas' own death (40 AD). FURTHER EVIDENCE for this CHRONOLOGY: 49 AD (i) Peter and Paul argue in Antioch (Acts 15; Gal 2) (ii) Emperor Claudius expells the Jews from Rome because of unrest evoked by Christians: "Since the Jews constantly made disturbances at the instigation of Chrestus, he [Emperor Claudius] expelled them from Rome" (Suetonius, Life of Claudius, 25:4; Acts 18:2) CONCLUSION: The expansion of the Messianic Mission to include Gentiles, begun by Paul on his First Missionary Journey (46-48 AD), was an explosive "hot button" issue*. It immediately sparked a fire-storm of controversy throughout World Jewry, from Judah to Antioch to Rome. The harsh words between Peter and Paul in Antioch were but a muted echo of the "flame-fest" that erupted elsewhere, particularly in Rome, where Emperor Claudius was prompted to actually expell the Jews from the city because of their unrest. * In Acts 22, Paul address the Jews in the Temple. The Jews listen patiently to him for several minutes, until he says: Acts 22:21-22 "And he [the Messiah] said to me, 'Go! For I will send you far away to the Gentiles.'" They listened to him up to this statement, and then they raised their voices and said, "Away with such a fellow from the earth, for he should not be allowed to live!"
PETER & PAUL espouse same Theology: Acts 15:8-9,11 (PETER) "And God, who knows the heart, testified to them giving them the Holy Spirit, just as He also did to us; and He made no distinction between us and them, cleansing their hearts by faith... But we believe that we are saved through the grace of the Lord Jesus, in the same way as they also are." Romans 3:23-24 (PAUL) For all have sinned and fall short of the glory of God, being justified as a gift by His grace through the redemption which is in Christ Jesus;