Haydock Catholic Bible Commentary
By the child, in this place, the apostles understands all the Jewish people, who, as long as they were under the childhood of the law, were subject to numerous restrictions, although they were the favorite children of God. But when the fulness of time came, they received the adoption of children, and were in possession of the liberty of the law of grace. They were no longer obliged to observe the legal rites. Whence the apostle wishes the conclusion to be drawn, that if persons once subject to the law were now exempt from it, how much more will those be excused from its yoke, who were never under its control. (Calmet)
Under the elements of the world. St. John Chrysostom understands the exterior ceremonies and precepts of the law of Moses, with an allusion to the first elements or rudiments which children are taught. (Witham)
The fulness of the time. That is, the time decreed by Divine Providence. --- God sent his Son made of a woman, who took a true human body of his virgin Mother. --- Under the law, as he was man, because he was pleased to make himself so. (Witham)
Crying, Abba. That is, Father; Christ taught us in prayer to call God our Father, he having made us his adoptive sons by his grace, and heirs of heaven. (Witham)
You served them, who by nature are no gods. These words are to be understood of the converts, who had been Gentiles. --- Known of God. That is, approved and loved by him. (Witham) --- The language of the apostle in this verse is not perhaps strictly precise. The Galatians, whom he addresses, had been converted from paganism, and of course were never subject to the law of Moses. But the apostle, by these words, entreats them not to begin now to serve these weak and useless elements, (as he calls the Jewish rites) or by this expression he may mean (as St. John Chrysostom and Theophylactus explain it) the tyranny of error and wickedness. (Calmet)
You observe  days, &c. These false teachers were for obliging all Christians to observe all the Jewish feasts, fasts, ceremonies, &c. Some of the later reformers find here an occasion to blame the fasts and holydays kept by Catholics. St. Jerome, in his commentary on these words, tells us that some had made the like objection in his time: his answer might reasonably stop their rashness; to wit, that Christians keep indeed the sabbath on Sunday, (not the Jewish sabbath on Saturdays) that they keep also divers holydays, and days on which great saints suffered martyrdom, (let our adversaries take notice of this) but that both the days are different, and the motives of keeping them. See St. Jerome, tom. iv. p. 271. (Witham) --- This text cannot mean to condemn the feasts appointed to be kept holy in the Catholic Church. For on the festivals dedicated to our Lord, St. Augustine writeth thus: "We dedicate and consecrate the memory of God's benefits with solemnities on solemn appointed days, lest in process of time they might creep into ungrateful and unkind oblivion." And of the martyrs thus: "Christians people celebrate the memories of martyrs with religious solemnity, both to move themselves to an imitation of their virtues, and that they may be partakers of their merits, and helped by their prayers." (Cont. Faust. lib. xx. chap. 21.) And of other saints thus: "keep ye and celebrate with sobriety the nativities of saints, that we may imitate them that are gone before us, and that they may rejoice in us, who pray for us." (In Ps. .xxxviii. Conc. 2. in fine.)
St. Jerome on this verse, p. 271, dicat aliquis, nos simile crimen inurrimus....observantes diem dominicam....Pascha festivitatem, & Pentecostes ætitiam, & pro varietate regionum, diversa in honore martyrum tempora constiuta, &c.
Be ye as I, for I also am as you. I add no word in the translation, because it is uncertain what is to be understood: some give this construction, be you as I am, because I also was, as you now are; and they expound them thus: lay aside your zeal for the Jewish ceremonies as I have done, who was once as zealous for them as you seem now to be. Others would have the construction and sense to be: be you as I am, because I am as you; that is, be affected to me, and love me, as I have still a true affection and love for you, which is agreeable to what follows, you have not offended me at all. (Witham)
Through infirmity of the flesh....and your temptation in my flesh. St. Jerome thinks the apostle had some bodily infirmity upon him. St. John Chrysostom understands his poverty, and want, and persecutions, and that some were inclined to contemn him and his preaching on these accounts. Yet others among them did not esteem him less: they received him, respected him as an Angel of God, as Christ Jesus; they would have given him their eyes, as one may say, and all that was dear to them. He puts them in mind how happy then they thought themselves, and asketh why they are now so much changed? (Witham)
Gal 4:17-20 tells them this change come from the false teachers among them, who with a false zeal would exclude them from a friendship and a submission to St. Paul, and deprive them again of that Christian liberty by which Christ, and the faith of Christ, had freed them from the yoke of the Mosaical law. On this account I must labor and travail, as it were to bring you forth a second time. How do I now wish to be with you, to change my voice, to exhort you, to reprehend you, to use all ways and means to regain you to Christ? --- I am in confusion about you, I am perplexed, as the Greek signifies, as not knowing what to say or do. (Witham)
Confundor in vobis, Greek: aporoumai. See 2 Corinthians iv. 8. &c.
It is written in the law, that is, in Genesis, (chap. xvi. and chap. xxi.) that Abraham had two sons, &c. that his two sons, Ismael, born of his servant, Agar, and Isaac of his wife, Sara, in an allegorical sense, represent the two testaments or covenants, which God made with his people: that by Ismael was represented that covenant of the former law delivered to Moses on Mount Sina, by which the Jews were made his elect people, yet as it were his servants, to be kept to their duty by fear of punishments; but by Isaac is represented the new covenant or testament of Christ, given at Jerusalem, where he suffered, where the new law was first published; by which law, they who believe in Christ were made the spiritual children of Abraham, the sons of God, and heirs of the blessings promised to Abraham: that Sina, the mountain in Arabia, hath an affinity with Jerusalem, and with here children, who remain under the servitude of the law of Moses: we cannot understand a conjunction, or an affinity, as to place and situation, Sina and Jerusalem being nearly twenty days' journey distant from each other; therefore it can only be an affinity in a mystical signification, inasmuch as Jerusalem was the capital of the Jews, where the children of those who received the law on Mount Sina lived still under the servitude of the same law: but Christians, who believe in Christ, must look upon themselves as belonging to Jerusalem, and not to the city of Jerusalem upon earth, but to the celestial Jerusalem in heaven, which is our mother, now no longer servants and slaves to the former law, but free, being made the sons of God by the grace of Christ, and heirs of heaven. And these blessings were promised to all nations, not only to the Jews, of which the much greater part remained obstinate, and refused to believe in Christ, but also particularly to the Gentiles, according to the prophecy of Isaias, (chap. liv.) rejoice thou that hast been barren, like Sara, for a long time; i.e. rejoice, you Gentiles, hitherto left in idolatry, without knowledge or worship of the true God, now you shall have more children among you than among the Jews, who were his chosen people. (Witham)
Qui conjunctus est ei, quæ nunc est Jerusalem, Greek: sustoichei te nun Ierousalem. See Budæus, Estius, Mr. Legh, &c.
Gal 4:29 . Paul makes another observation upon this example of Ismael and Isaac: that as Ismael was troublesome to Isaac, for which he and his mother were turned out of the family, so also now the Jews insulted and persecuted the Christians, who had been Gentiles; but God will protect them as heirs of the blessings promised: they shall be accounted the spiritual children of Abraham, while the Jews, with their carnal ceremonies, shall be cast off. (Witham) --- This, says St. Augustine, is a figure of heretics, (who are the children of the bond-woman) unjustly persecuting the Catholic Church. (Ep. 48.)