Galatians 4:6

because ye are sons--The gift of the Spirit of prayer is the consequence of our adoption. The Gentile Galatians might think, as the Jews were under the law before their adoption, that so they, too, must first be under the law. Paul, by anticipation, meets this objection by saying, YE ARE sons, therefore ye need not be as children (Gal 4:1) under the tutorship of the law, as being already in the free state of "sons" of God by faith in Christ (Gal 3:26), no longer in your nonage (as "children," Gal 4:1). The Spirit of God's only Begotten Son in your hearts, sent from, and leading you to cry to, the Father, attests your sonship by adoption: for the Spirit is the "earnest of your inheritance" (Rom 8:15-16; Eph 1:13). "It is because ye are sons that God sent forth" (the Greek requires this translation, not "hath sent forth") into OUR (so the oldest manuscripts read for "your," in English Version) hearts the Spirit of His son, crying, "Abba, Father" (Joh 1:12). As in Gal 4:5 he changed from "them," the third person, to "we," the first person, so here he changes from "ye," the second person, to "our," the first person: this he does to identify their case as Gentiles, with his own and that of his believing fellow countrymen, as Jews. In another point of view, though not the immediate one intended by the context, this verse expresses, "Because ye are sons (already in God's electing purpose of love), God sent forth the Spirit of His Son into your hearts," &c.: God thus, by sending His Spirit in due time, actually conferring that sonship which He already regarded as a present reality ("are") because of His purpose, even before it was actually fulfilled. So Heb 2:13, where "the children" are spoken of as existing in His purpose, before their actual existence. the Spirit of his Son-…

The apostle, in this chapter, is still carrying on the same general design as in the former - to recover these Christians from the impressions made upon them by the judaizing teachers, and to represent their weakness and folly in suffering themselves to be drawn away from the gospel doctrine of justification, and to be deprived of their freedom from the bondage of the law of Moses. For this purpose he makes use of various considerations; such as, I. The great excellence of the gospel state above the legal (Gal 4:1-7). II. The happy change that was made in them at their conversion (Gal 4:8-11). III. The affection they had had for him and his ministry (Gal 4:12-16). IV. The character of the false teachers by whom they had been perverted (Gal 4:17, Gal 4:18). V. The very tender affection he had for them (Gal 4:19, Gal 4:20). VI. The history of Isaac and Ishmael, by a comparison taken from which he illustrates the difference between such as rested in Christ and such as trusted in the law. And in all these, as he uses great plainness and faithfulness with them, so he expresses the tenderest concern for them.

4:6 The Holy Spirit provides an inner testimony to assure us that we are God’s children (see Rom 8:16; Eph 1:13-14). • Those who have the Spirit of his Son are able to address God as Father, just as Christ did (Mark 14:36; cp. Matt 6:9).