The Galatians to whom the letter is addressed were Paul’s converts, most likely among the descendants of Celts who had invaded western and central Asia Minor in the third century B.C. and had settled in the territory around Ancyra (modern Ankara, Turkey). Paul had passed through this area on his second missionary journey (Acts 16:6) and again on his third (Acts 18:23). It is less likely that the recipients of this letter were Paul’s churches in the southern regions of Pisidia, Lycaonia, and Pamphylia where he had preached earlier in the Hellenized cities of Perge, Iconium, Pisidian Antioch, Lystra, and Derbe (Acts 13:13-14:27); this area was part of the Roman province of Galatia, and some scholars think that South Galatia was the destination of this letter.
if it is addressed to the Galatians in the north, the letter was probably written around A.D. 54 or 55, most likely from Ephesus after Paul’s arrival there for a stay of several years on his third missionary journey (Acts 19; Acts 20:31). On the South Galatian theory, the date would be earlier, perhaps A.D. 48-50. Involved is the question of how one relates the events of Gal 2:1-10 to the "Council of Jerusalem" described in Act 15 (see the notes on each passage).
In any case, the new Christians whom Paul is addressing were converts from paganism (Gal 4:8-9) who were now being enticed by other missionaries to add the observances of the Jewish law, including the rite of circumcision, to the cross of Christ as a means of salvation. For, since Paul’s visit, some other interpretation of Christianity had been brought to these neophytes, probably by converts from Judaism (the name "Judaizers" is sometimes applied to them); it has specifically been suggested that they were Jewish Christians who had come from the austere Essene sect.
These interlopers insisted on the necessity of following certain precepts of the Mosaic law along with faith in Christ. They were undermining Paul’s authority also, asserting that he had not been trained by Jesus himself, that his gospel did not agree with that of the original and true apostles in Jerusalem, that he had kept from his converts in Galatia the necessity of accepting circumcision and other key obligations of the Jewish law, in order more easily to win them to Christ, and that his gospel was thus not the full and authentic one held by "those of repute" in Jerusalem (Gal 2:2). Some scholars also see in Gal 5; 6 another set of opponents against whom Paul writes, people who in their emphasis on the Spirit set aside all norms for conduct and became libertines in practice.
When Paul learned of the situation, he wrote this defense of his apostolic authority and of the correct understanding of the faith. He set forth the unique importance of Christ and his redemptive sacrifice on the cross, the freedom that Christians enjoy from the old burdens of the law, the total sufficiency of Christ and of faith in Christ as the way to God and to eternal life, and the beauty of the new life of the Spirit. Galatians is thus a summary of basic Pauline theology. Its themes were more fully and less polemically developed in the Letter to the Romans.
Autobiographically, the letter gives us Paul’s own accounts of how he came to faith (Gal 1:15-24), the agreement in "the truth of the gospel" (Gal 2:5, 14) that he shared with the Jewish Christian leaders in Jerusalem, James, Kephas, and John (Gal 2:1-10), and the rebuke he had to deliver to Cephas in Antioch for inconsistency, contrary to the gospel, on the issue of table fellowship in the racially mixed church of Jewish and Gentile Christians in Antioch (Gal 2:11-14; cf Gal 2:15-21). At the conclusion of the letter (Gal 6:11-18), Paul wrote in his own hand (cf 2 Thes 3:17-18) a vivid summary of the message to the Galatians.
In his vigorous emphasis on the absolute preeminence of Christ and his cross as God’s way to salvation and holiness, Paul stresses Christian freedom and the ineffectiveness of the Mosaic law for gaining divine favor and blessings (Gal 3:19-29). The pious Jew saw in the law a way established by God to win divine approval by a life of meticulous observance of ritual, social, and moral regulations. But Paul’s profound insight into the higher designs of God in Christ led him to understand and welcome the priority of promise and faith (shown in the experience of Abraham, Gal 3:6-18) and the supernatural gifts of the Spirit (Gal 3:2-5; 5:16-6:10). His enthusiasm for this new vision of the life of grace in Christ and of the uniquely salvific role of Christ’s redemptive death on the cross shines through this whole letter.
The principal divisions of the Letter to the Galatians are the following:
I. Address (Gal 1:1-5)
II. Loyalty to the Gospel (Gal 1:6-10)
III. Paul’s Defense of His Gospel and His Authority (Gal 1:11-2:21)
IV. Faith and Liberty (Gal 3:1-4:31)
V. Exhortation to Christian Living (Gal 5:1-6:10)
VI. Conclusion (Gal 6:11-18)