The first two chapters of this Epistle are therefore Paul's _Apologia pro vita sua_. With certain chapters in 2 Corinthians, and scattered passages in other letters, they form the Apostle's autobiography, one of the most perfect self-portraitures that literature contains. They reveal to us the man more effectively than any ostensible description could have done. They furnish an indispensable supplement to the external and cursory delineations given in the Acts of the Apostles. While Luke skilfully presents the outward framework of Paul's life and the events of his public career, it is to the Epistles that we turn--to none more frequently than this--for the necessary subjective data, for all that belongs to his inner character, his motives and principles. This Epistle brings into bold relief the Apostle's moral physiognomy. Above all, it throws a clear and penetrating light on the event which determined his career--the greatest event in the history of Christianity after the Day of Pentecost--Paul's conversion to faith in the Lord Jesus.
This was at once the turning-point in the Apostle's life, and the birth-hour of his gospel. If the Galatians were to understand his teaching, they must understand this occurrence; they must know why he became a Christian, how he had received the message which he brought to them. They would, he felt sure, enter more sympathetically into his doctrine, if they were better acquainted with the way in which he had arrived at it. They would see how well-justified was the authority, how needful the severity with which he writes. Accordingly he begins with a brief relation of the circumstances of his call to the service of Christ, and his career from the days of his Judaistic zeal, when he made havoc of the faith, till the well-known occasion on which he became its champion against Peter himself, the chief of the Twelve (ch. i. 11-ii. 21.) His object in this recital appears to be threefold: to refute the misrepresentations of the Circumcisionists; to vindicate his independent authority as an Apostle of Christ; and further, to unfold the nature and terms of his gospel, so as to pave the way for the theological argument which is to follow, and which forms the body of the Epistle.