Matthew Poole's Commentary
Galatia (to the churches in which country this Epistle is directed) is by all agreed to be a part of Asia the Lesser, now under the power of the Turks, and by them called Chiangare. Geographers tell us, it is bounded on the west by Phrygia the Greater, (now called Germian), Bithynia, (now called Becksangel), and Asia Propria, a country of Anatolia; on the south, with Pisidia, (now called Versacgeli), and Licaonia (now called Cogni); on the east, with Cappadocia (now called Amasia); and on the north, with Paphlagonia (now called Bolli). The whole country was anciently called Gallo-Grecia, from some French, who, leaving their country and coming to inhabit there, gave it that name. It had in it several cities, amongst which geographers reckon Ancyra, Synopa, Pompeiopolis, Claudiopolis, Nicopolis, Laodicea, to which also some count Antioch. When or by whose ministry this people first received the gospel, we do not read. Paul travelled thither, Act 16:6, but was at that time forbidden of the Holy Ghost to preach there; but, Act 18:23, it is said, that when he had spent some time at Antioch, he departed, and went over all the country of Galatia and Phrygia in order, strengthening all the disciples. This was about two years after that he was forbidden to preach there, in which time the gospel was planted and disciples made in this country.
At what time Paul wrote this Epistle to them is very uncertain; some think that it was written much at the same time when the Epistle to the Romans was written (the argument being much the same with that of that Epistle). Others think it was written at Rome during his last imprisonment, because he saith, Gal 6:17, that he bare in his body the marks of the Lord Jesus. It is manifest that it was written at some distance of time after the first plantation of the gospel there, for the enemy had had time to sow tares.
The occasion of writing it, was partly to reprove the members of this church, for their apostacy from the doctrine of the gospel, as to justification; partly to set them right again in it, and to vindicate himself from the aspersions and imputations which their false teachers had cast upon him, in order to their better success with their new doctrine.
The new doctrine brought in by these false teachers, was the necessity of circumcision, and other works of the law, as well as faith in Christ, in order to the justification of the sinner before God; which they pressed rather upon a politic, than any religious consideration, as being the way to avoid that persecution which at that time attended all Christians; from which imputation, those who were circumcised, though they also professed faith in Christ, saved themselves. To buoy up themselves they vilified the apostle Paul to these churches, as being no apostle, one that had learned all which he knew from James, and Peter, and John; yet varied from them as to his doctrine and practice, yea, from himself also.
The two first chapters of this Epistle are mostly spent in the apostle's vindication of himself; proving himself to be a true apostle, and not to have learned what he taught from Peter, or James, or John, but that he had it by revelation from Jesus Christ. In the two following chapters he proves the doctrine of justification by faith in Christ, ( in opposition to the justification taught by these false teachers, by the works of the law), by various arguments. In the two last chapters, he presseth their standing fast in the liberty wherewith Christ had made them free, together with several other things, which are the common duties of all Christians. Then closeth his Epistle, with praying grace, mercy, and peace, to be their, and all true Christians', portion.