With regard to the genuineness and authenticity of this epistle, no writer of any credit or respectability has expressed any doubts. Its Pauline origin is attested not only by the superscription which it bears, if this be genuine, but also by frequent allusions in the course of it to the great apostle of the Gentiles. It is corroborated also by the style, tone, and contents of the epistle, which are perfectly in keeping with those of the other writings of the apostle. The testimony of the early Church on this subject is most decisive and unanimous.
The parties to whom this characteristic letter was addressed are described in the epistle itself as "the churches of Galatia" in Asia Minor, otherwise called Gallogriecia, a province that bore in its name its well-founded claim to a Gallic or Celtic origin and that now, after an establishment, first by predatory conquest, and subsequently by recognition but limitation at the hands of neighbouring could date an occupancy, though not an independence, extending to more than three hundred years; the first subjection of Galatia to the Romans having taken place in B.C. 189 and its formal reduction to a regular Roman province in A.D. 26.
Into this district the Gospel was first introduced by Paul himself. Churches were then also probably formed, for on revisiting this district some time after his first visit it is mentioned that he "strengthened the disciples." These churches seem to have been composed principally of converts directly from heathenism but partly, also, of Jewish converts, both pure Jews and proselytes. Unhappily, the latter, not thoroughly emancipated from early opinions and prepossessions, or probably influenced by Judaic teachers who had visited these churches, had been seized with a zealous desire to incorporate the rites and ceremonies of Judaism (especially circumcision, with the spiritual truths and simple ordinances of Christianity.
So active had this party been in disseminating their views on this head through the churches of Galatia, that the majority at least of the members had been seduced to adopt them. To this result it is probable that the previous religious conceptions of the Galatians contributed; for, accustomed to the worship of Cybele, which they had learned from their neighbours the Phrygians, and to theosophist doctrines with which that worship was associated, they would be the more readily induced to believe that the fullness of Christianity could alone be developed through the symbolical shadows of an elaborated ceremony. It would seem that on his last visit to this region, Paul found the leaven of Judaism beginning to work in the churches of Galatia, and that he then warned them against it in language of the most decided character. From some passages in this epistle it would appear also that insinuations had been disseminated among the Galatian churches to the effect that Paul was not a divinely-commissioned apostle, but only a messenger of the church at Jerusalem; that Peter and he were at disagreement upon the subject of the relation of the Jewish rites to Christianity; and that Paul himself was not at all times so strenuously opposed to those ordinances as he had chosen to be among the Galatians. Of this state of things intelligence having been conveyed to the apostle, he wrote this epistle for the purpose of vindicating his own pretensions and conduct, of counteracting the influence of these false views, and of recalling the Galatians to the simplicity of the Gospel which they had received. The importance of the case was probably the reason why the apostle put himself to the great labor of writing this epistle with his own hand.