Galatians 4:21 - Joseph Benson’s Commentary on the Old and New Testaments

Tell me, ye that desire to be under the law Of Moses, as the rule of your justification; do ye not hear the law? Regard what it says? how it teaches that Abraham's children, by faith, who are heirs of the promises, are free from the bondage of the law? “The argument the apostle is going to use being taken from the law of Moses, was urged with much propriety, not only against the Judaizers, who affirmed that obedience to the law of Moses was necessary to men's salvation, but against those Gentiles also whom the Judaizers had seduced to receive the law. For if the apostle made it evident, from the law of Moses itself, that Abraham's children, by faith, were free from the bondage of the law, no further argument was necessary to prove that obedience to the law is not necessary to justification.” Macknight. It is written that Abraham had two sons Here he illustrates the doctrine of justification by faith, and of the abolition of the legal dispensation, by the history of Abraham's family, in which it was prefigured. The plain import of what he advances is this: That as in Abraham's family there were two mothers, and two sorts of children, which were differently treated; so, in the visible church, there are two sorts of professors; some that seek justification by the works of the law, who are in a servile and miserable condition, and shall at last be cast out from the presence of God, and the society of the saints; others that seek justification by faith in Christ, and in the promises of God through him: and these are the free sons of God's family, and in a happy condition, and shall at last certainly obtain the inheritance of eternal life. The one Namely, Ishmael, by Hagar, a bond-maid, the other Namely, Isaac, by Sarah, a free-woman. But there was a great difference between them; for he who was of the bond-woman That is, Ishmael; was born only after the flesh In the common order of nature, without any particular promise of God, or any unusual interposition of his power and providence. But he of the free-woman That is, Isaac; was by promise Through the strength supernaturally communicated to his parents by the promise, Lo Sarah, thy wife, shall have a son; and, like his mother, being free, was his father's heir.