When the preparatory stage had come to an end and the world was ripe for the new development, God sent forth His Son, born of a woman, born under the Law, to redeem them which were under the Law, that we might receive the adoption of sons.
It seems almost incredible to the outsider, who judges evidence after the ordinary methods of historical students, that this verse should be quoted by some scholars as proof that Paul understood and believed Jesus to be plainly and literally “the son of Joseph”. Yet the opinion has been strenuously and confidently maintained that Paul was ignorant of any idea that Jesus, so far as concerned His birth, was anything else except, in the strictest sense, Joseph’s son. But the words which Paul here uses plainly imply the following points in his belief and in his teaching to the Galatians: —
1. Jesus existed in the fullest sense as the Son of God before He was sent forth into the world.
2. He was sent forth with a definite duty to perform, retaining the same nature and personal character in the performance of this duty that He had previously possessed. That is proved by the common use in Luke of the verb “sent forth” (ἐξαποστέλλεν), and its natural sense as the dispatching of a suitable messenger, qualified by his personal character and nature, for the duty to which He is sent.
3. For this duty Jesus took human form and nature: the words γενόμενον ἐκ γυναικός; express simply that He became a man among men.
4. To discharge this duty, it was indispensable that Jesus should be subject to the Law, in order to show in His own case how by dying to the Law a man rises superior to it: thus His death was the purchase of men, paid in order that they might be placed in a position to avail themselves of the adoption as sons, open to them by the Diatheke of the Father. He could show them the way only by traversing it before them.
It is clear that the teaching, so briefly summed up in this verse, is to be understood as already familiar to the Galatians; Paul is merely revivifying it in their memory. And, in the discourse which Luke gives as typical of Paul’s teaching in Pisidian Antioch and elsewhere (Act 13:16-41), exactly the same teaching is set forth in very simple language — language so simple that its full meaning hardly impresses itself on the reader until he compares it with the Epistle. Paul there quotes “Thou art My Son”; and he says “the Word of this salvation is sent forth to us,” using the same verb as in Gal 4:4. The context shows that “the Word” here is not to be taken in the mere sense of news or spoken words, ῥήματα (as Meyer-Wendt explain): it is used in a more mystical sense, and it forms the transition from the simpler expression of the Synoptics to the language used about “the Word” in the Fourth Gospel. That Luke employs this term in his brief abstract of Paul’s Galatian teaching, must be taken as a proof that Paul intentionally expressed himself in mystic language as to the relation between the Father and the Son. That was not a subject about which he spoke openly.
It has often seemed to me that this was the subject about which he “heard unspeakable words which it is not lawful for man to utter” in the vision described in 2Co 12:4. Though it is vain to seek to know the contents of a vision, which the seer pointedly refuses to speak about, yet the mystic language which Paul uses on this subject may justify, perhaps, a conjecture as to the subject.
The peroration of the address at Pisidian-Antioch insisted on the marvelous and mysterious nature of God’s action in sending forth His Son: “I work a wonder in your days, a work which you would not believe, if one should recount it to you”.