The interpretation timeline
Galatians 4:5 Douay-Rheims

That he might redeem them who were under the law: that we might receive the adoption of sons.

A.D. 220 – 1871 7 witnesses

Patristic

before A.D. 750
220
A.D.
Tertullian Patristic
c. A.D. 150–220
“But as for that idle god, who has neither any work nor any prophecy, nor accordingly any time, to show for himself, what has he ever done to bring about the fulness of time, or to wait patiently its completion? If nothing, what an impotent state to have to wait for the Creator's time, in servility to the Creator! But for what end did He send His Son? "To redeem them that were under the law," in other words, to "make the crooked ways straight, and the rough places smooth," as Isaiah says -in order that old things might pass away, and a new course begin, even "the new law out of Zion, and the word of the Lord from Jerusalem," and "that we might receive the adoption of sons," that is, the Gentiles, who once were not sons.”
Source
407
A.D.
John Chrysostom Patristic
A.D. 347–407
“Here he states two objects and effects of the Incarnation, deliverance from evil and supply of good, things which none could compass but Christ. They are these; deliverance from the curse of the Law, and promotion to sonship. Fitly does he say, that we might "receive," "[be paid,]" implying that it was due; for the promise was of old time made for these objects to Abraham, as the Apostle has himself shown at great length. And how does it appear that we have become sons? he has told us one mode, in that we have put on Christ who is the Son; and now he mentions another, in that we have received the Spirit of adoption.”
Source
430
A.D.
Augustine of Hippo Patristic
A.D. 354–430
“He says "adoption" so that we may clearly understand that the Son of God is unique. For we are sons of God through his generosity and the condescension of his mercy, whereas he is Son by nature, sharing the same divinity with the Father.”

Scholastic

c. 1100 – 1500
1273
A.D.
Thomas Aquinas Catholic
1225–1274
“Here the Apostle adapts the proposed similitude to Christ. And first the adaptation itself is set forth; second, the end of the matter to which the similitude is adapted, at the place "that he might redeem those who were under the law," etc. It should be known that above, in the proposed similitude, he showed four things in order, as has been said. Here, however, in adapting those four things to Christ, he begins from the last, namely from the determination of time, the reason for which is that it was the same time in which Christ was humbled and in which the faithful were exalted. And therefore he says, "but when the fullness of time came," that is, after the time which had been predetermined by God the Father concerning the sending of his Son was completed; and it is taken in this way in Luke 2:6: "the days were fulfilled," etc. That time, moreover, is called full on account of the fullness of graces which are given in it, according to Psalm 64:10: "the river of God is filled with water," etc. Likewise on account of the fulfillment of the figures of the old law. Matthew 5:17: "I have not come to destroy the law," etc. Likewise, on account of the fulfillment of the promises. Daniel 9:27: "And he shall confirm the covenant with many for one week." Now this that he says, "but when the fullness of time came," etc. — and likewise in other places of Scripture where the time concerning Christ is said to be fulfilled — is not to be referred to fatal necessity, but to divine ordination, concerning which it is said in Psalm 118:91: "by your ordinance the day continues," etc. A twofold reason, moreover, is assigned as to why that time was preordained for the coming of Christ. One is taken from greatness. For since he who was to come was great, it was fitting that men be disposed toward his coming by many signs and many preparations. Hebrews 1:1: "in many parts and in many ways," etc. The other is from the condition of the one coming. For since a physician was to come, it was fitting that before his coming men be convicted of their disease, both as to the defect of knowledge under the law of nature and as to the defect of virtue under the written law. And therefore it was fitting that both, namely the law of nature and the law of Scripture, precede the coming of Christ. Second, he adapts the similitude as regards the dignity of inheritance, when he says "God sent his Son," namely his own and natural Son. And if a son, then also an heir. He says, moreover, "his Son," that is, his own, natural, and only-begotten Son, not an adoptive one. John 3:16: "so God loved the world, that," etc. He sent him, I say, not separated from himself, because he was sent by this, that he assumed human nature, and yet he was in the bosom of the Father — John 1:18: "the only-begotten, who is in the bosom of the Father" — eternally. John 3:13: "No one has ascended into heaven, except he who descended from heaven, the Son of Man who is in heaven," who, although he descended through the assumption of flesh, nevertheless is in heaven. Likewise he sent him, not that he might be where before he was not; because, although he came into his own through the presence of the flesh, yet he was in the world through the presence of his deity, as is said in the Gospel, John 1:14. Similarly he did not send him as a servant, because his mission was the assumption of flesh, not the laying aside of majesty. God therefore sent his Son to heal, I say, the deviation of the concupiscible appetite, and to illumine the ignorance of the rational creature. Psalm 106:20: "he sent his word," etc. He also sent him to free men from the power of the Devil, against the infirmity of the irascible appetite. Isaiah 19:20: "he will send them a savior, who will free them." Likewise as a remedy from the obligation of eternal death. Hosea 3:14: "from the hand of death I will free them, from death I will redeem them." Likewise to save them from their sins. John 3:17: "God did not send his Son into the world to judge the world, but that the world might be saved through him," etc. Third, he adapts the similitude as regards smallness, when he says "made of a woman." Isaiah 9:6: "a little child is born to us," etc. Philippians 2:7: "he emptied himself," etc. He made himself small, not by relinquishing his greatness, but by assuming smallness. Now in this that he says "made of a woman," two errors are to be guarded against. The first is that of Photinus, who said that Christ was a mere man and took the beginning of his being from the Virgin; and so he says that he was made of a woman as though he had taken his entire beginning from her. But this is false, because it is against what is said in Romans 1:3: "who was made to him of the seed of David according to the flesh"; it does not say "according to the person," which is from eternity, namely the very hypostasis of the Son of God. Hence, just as when a shield newly becomes white, it is not necessary to say that the very substance of the shield newly comes to be, but that whiteness has newly come to it, so from the fact that the Son of God newly assumed flesh, it is not necessary to say that the person of Christ was newly made, but that a human nature newly came to him, just as certain things happen to a body without any change in the body itself. For some things come to a thing and change it, as absolute forms and qualities; but certain things come without change, and of this sort is the assumption of flesh, inasmuch as it expresses a relation. Hence by this the person of the Word is changed in nothing. And hence it is that in speaking of divine things we use terms that signify relation even from time. Hence we say, in that verse of Psalm 89:1, "Lord, you have become a refuge for us," and that God became man. But we do not use absolute forms and qualities, as: "God became good, wise," and the like. Likewise the error of Ebion is to be avoided, who said that Christ was born of the seed of Joseph, moved to posit this by the fact that it says "of a woman." For, according to him, "woman" implies only corruption. But this is false, because this name "woman," in sacred Scripture, also designates the natural sex, according to that verse of Genesis 3:12: "the woman whom you gave me," etc. For he calls her "woman" who nevertheless was still a virgin. By this also, that it is said "made of a woman," two errors are destroyed: namely that of Valentinus, who said that Christ did not take a body from the Virgin, but brought it from heaven, and passed through the blessed Virgin as through a pipe or channel. But this is false, because if what he says were true, Christ would not have been made of a woman, as the Apostle says; for this preposition, "of," designates a material cause. Likewise, the error of Nestorius, who said that the blessed Virgin is not the mother of the Son of God, but of the son of man: this is shown to be false by this, that the Apostle says here that God sent his Son made of a woman. For he who is made of a woman is her son. If therefore the Son of God was made of a woman, namely of the blessed Virgin, it is manifest that the blessed Virgin is the mother of the Son of God. Although, however, it could be said "born of a woman," he nevertheless says pointedly "made," and not "born." For for something to be born is for it to be produced only from a conjoined principle, but to be made is also from a separate principle. For an ark is made by a craftsman, but fruit is born from a tree. The principle of human generation, however, is twofold: namely material — and as to this Christ proceeded from a conjoined principle, because he took the matter of his body from the Virgin. Hence according to this he is said to be born of her. Matthew 1:16: "of whom Jesus was born," etc. The other is the active principle, which indeed in Christ, as to that which it had as a principle, that is, as to the formation of the body, was not conjoined but separate, because the power of the Holy Spirit formed it. And as to this he is not said to be born of a woman but made, as it were from an exterior principle. From which it is clear that when he said "of a woman," this does not signify corruption, for otherwise he would have said "born" and not "made." Fourth, he adapts the similitude as regards subjection, when he says "made under the law." But against this is what is said below, 5:18: "if you are led by the Spirit, you are not under the law." If therefore Christ is not only spiritual but even the giver of the Spirit, it seems unfitting to say that he was made under the law. I respond. It must be said that "to be under the law" is said in two ways. In one way, so that the word "under" denotes only the observance of the law, and in this way Christ was made under the law, because he was circumcised and presented in the temple. Matthew 5:17: "I have not come to destroy the law," etc. In another way, so that the word "under" denotes oppression. And in this way he is said to be under the law who is oppressed by fear of the law, and in this way neither Christ nor spiritual men are said to be under the law. Consequently, when he says "that those who were under the law," etc., he sets forth the fruit of the matter to which the similitude is adapted, namely that he willed for this reason to become subject at that time, so that they might become heirs, great and free. And he sets forth these two things: first, the fruit of liberation against subjection. And therefore he says "that he might free those who were under the law," that is, under the curse and burden of the law. Above, 3:13: "Christ redeemed us from the curse of the law," etc. Second, the fruit of exaltation, inasmuch as we are adopted as sons of God through this, that we receive the Spirit of Christ and are conformed to him. Romans 8:9: "if anyone does not have the Spirit of Christ," etc. And this adoption belongs in a special way to Christ, because we cannot become adoptive sons unless we are conformed to the natural Son. Romans 8:29: "whom he foreknew to be conformed to the image of his Son," etc. And as to this he says "that we might receive the adoption of sons," that is, that through the natural Son of God we might be made adoptive sons according to grace, through Christ.”

Post-Reformation

c. 1650 – 1900
1771
A.D.
John Gill Reformed
1697–1771
“To redeem them that were under the law,.... By whom are meant chiefly the Jews, who are elsewhere represented as in and under the law, in distinction from the Gentiles who were without it; see Rom 2:12 the Gentiles indeed, though they were not under the law of Moses, yet were not without law to God, they were under the law of nature. The law was given to Adam as a covenant of works, and not to him as a single person, but as a federal head to all his posterity; hence he sinning, and they in him, they all came under its sentence of condemnation and death, God's elect not excepted, and who are the persons said to be redeemed; for Christ was not sent to redeem all that were under the law; for as all mankind were included in it as a covenant of works made with Adam, and all are transgressors of it, the whole world is pronounced guilty before God by it, and liable to the curse of it; but not all mankind, only some out of every kindred, tongue, people, and nation, are redeemed by Christ, even all the elect, whether among Jews or Gentiles. The chosen among the Jews seem to be here principally designed; the redemption of them, which is the end of Christ's being sent, intends not only a deliverance of them from sin and Satan, and the world, to whom they were in bondage, but from the law under which they were; from the bondage of the ceremonial, and from the curse and condemnation of the moral law: that we might receive the adoption of children; by which may be meant, both the grace, blessing, and privilege of adoption, and the inheritance adopted to; both are received, and that in consequence of redemption by Christ; and such as receive the one will also receive the other. Adoption, as a blessing of grace, exists before it is received; nor does the reception of it add anything to the thing itself; it was in God's designation from all eternity, who predestinated his chosen ones unto it by Christ, according to the good pleasure of his will; it was provided, laid up, and secured for them in the everlasting covenant; and is part of that grace given them in Christ before the world began; but sin intervening, whereby the law was broken, obstacles were thrown in the way of God's elect receiving and enjoying this privilege in their own persons; wherefore Christ was sent to redeem them from sin and the law, and by so doing remove these obstructions, that so they might receive this privilege in a way consistent with the righteousness and holiness of God, as well as with his grace and goodness: receiving of it shows it to be a gift, a free grace gift, and not owing to any merit of the creature; faith is the hand which receives it, as it does all other blessings, as Christ himself, grace out of his fulness, righteousness, pardon, &c. and has no more causal influence on this than on any of these; faith does not make any the sons of God, or put them among the children; but receives the power, the authority, the privilege from God through Christ, under the witnessings of the spirit of adoption; whereby they become such, and have a right to the heavenly inheritance, which they shall hereafter enjoy.”
Source
1832
A.D.
Adam Clarke Methodist
1762–1832
“To redeem them - Εξαγορασῃ· To pay down a price for them, and thus buy them off from the necessity of observing circumcision, offering brute sacrifices, performing different ablutions, etc., etc. That we might receive the adoption of sons - Which adoption we could not obtain by the law; for it is the Gospel only that puts us among the children, and gives us a place in the heavenly family. On the nature of adoption see the notes on Rom 8:15.”
Source
1871
A.D.
1871
“To--Greek, "That He might redeem." them . . . under the law--primarily the Jews: but as these were the representative people of the world, the Gentiles, too, are included in the redemption (Gal 3:13). receive--The Greek implies the suitableness of the thing as long ago predestined by God. "Receive as something destined or due" (Luk 23:41; Jo2 1:8). Herein God makes of sons of men sons of God, inasmuch as God made of the Son of God the Son of man [AUGUSTINE on Psalm 52].”
Source
Modern · 1953 →

The in-app commentary runs from the Fathers to the early-modern record, then stops — that's where the public-domain sources end, not where the reading does. For the modern reading, follow the sources directly.