Jerome, Commentary on Galatians, [J.P. Migne, Editor]. Patrologiae Tomus XXVI. Paris: D’Ambroise, Pres La Barriere D’Enfer, ou Petit-Montrouge, 1845. pp. 307-438.
Jerome comments on Galatians 4:1 that the young heir Paul references, who in practice is no different from a slave, is a depiction of all the descendants of Adam up to the time of Christ (Jerome, Galatians, 370). In Christ, though, Jerome observes that we are built up as the mature heirs, referring to Ephesians 2. The problem Jerome identifies in humans is that we do not realize the freedom God gave us in Christ. When we recognize that we are in Christ, the second Adam, we no longer need the tutors and guardians.
Lest anyone should feel inferior to the apostles, in verse three Paul comments that “we” were subject to the elements of this world. Jerome points out that all creation and the natural understanding of life and philosophy rule us, but that Jesus is the one who delivers us from all of that (Jerome, Galatians, 371). It is therefore not entirely our maturity which makes us like the adult heir, but it is Jesus’ work which accomplishes our salvation.
In verse four, then, we see that Jesus himself was born under the law, so we could receive the adoption as sons (Jerome, Galatians, 372). Jerome draws a distinction between Jesus being born “ex” a woman, as opposed to the Marcionites who consider him born “per” a woman. Jerome does not explain the distinction very thoroughly. Yet he goes on to say that the salvation we desire cannot possibly come through obedience to the law, but by the justification given by grace. Christ redeemed his people from the law. He adopted them. It is by this means that they receive the position as the mature heirs of God.