The design of this chapter is, to show the effect of being under the Law, and the inconsistency of that kind of bondage or servitude with the freedom which is vouchsafed to the true children of God by the gospel. It is, in accordance with the whole drift of the Epistle, to recall the Galatians to just views of the gospel; and to convince them of their error in returning to the practice of the Mosaic rites and customs. In the previous chapter he had shown them that believers in the gospel were the true children of Abraham; that they had been delivered from the curse of the Law; that the Law was a schoolmaster to lead them to Christ, and that they were all the children of God. To illustrate this further, and to show them the true nature of the freedom which they had as the children of God, is the design of the argument in this chapter. He therefore states:
(1) That it was under the gospel only that they received the full advantages of freedom; Galatians 4:1-5. Before Christ came, indeed, there were true children of God, and heirs of life. But they were in the condition of minors; they had not the privileges of sons. An heir to a great estate, says the apostle Galatians 4:1-2, is treated substantially as if he were a servant. He is under tutors and governors: he is not permitted to enter on his inheritance; he is kept under the restraint of law. So it was with the people of God under the Law of Moses. They were under restraints, and were admitted to comparatively few of the privileges of the children of God. But Christ came to redeem those who were under the Law, and to place them in the elevated condition of adopted sons; Galatians 4:4-5. They were no longer servants; and it was as unreasonable that they should conform again to the Mosaic rites and customs, as it would be for the heir of full age, and who has entered on his inheritance, to return to the condition of minorship, and to be placed again under tutors and governors, and to be treated as a servant.
(2) as sons of God, God had sent forth the Spirit of his Son into their hearts, and they were enabled to cry Abba, Father. They were no longer servants, but heirs of God, and should avail themselves of the privileges of heirs; Galatians 4:6-7.
(3) sustaining this relation, and being admitted to these privileges, the apostle remonstrates with them for returning again to the "weak and beggarly elements" of the former dispensation - the condition of servitude to rites and customs in which they were before they embraced the gospel; Galatians 4:8-11. When they were ignorant of God, they served those who were no gods, and there was some excuse for that; Galatians 4:8. But now they had known God, they were acquainted with his laws; they were admitted to the privileges of his children; they were made free, and there could be no excuse for returning again to the bondage of those who had no true knowledge of the liberty which the gospel gave. Yet they observed days and times as though these were binding, and they had never been freed from them Galatians 4:10; and the apostle says, that he is afraid that his labors bestowed on them, to make them acquainted with the plan of redemption, had been in vain.
(4) to bring them to a just sense of their error, he reminds theta of their former attachment to him, Galatians 4:12-20. He had indeed preached to them amidst much infirmity, and much that was suited to prejudice them against him Galatians 4:13; but they had disregarded that, and had evinced toward him the highest proofs of attachment - so, much so, that they had received him as an angel of God Galatians 4:14, and had been ready to pluck out their own eyes to give them to him, Galatians 4:15. With great force, therefore, he asks them why they had changed their views toward him so far as to forsake his doctrines? Had he become their enemy by telling the truth? Galatians 4:16. He tenderly addresses them, therefore, as little children, and says, that he has the deepest solicitude for their welfare, and the deepest anxiety on account of their danger - a solicitude which he compares Galatians 4:19, with the pains of childbirth.
(5) in order to enforce the whole subject, and to show the true nature of the conformity to the Law compared with the liberty of the gospel, he allegorizes an interesting part of the Mosaic history - the history of the two children of Abraham; Galatians 4:21-31. The condition of Hagar - a slave - under the command of a master - harshly treated - cast out and disowned, was an apt illustration of the condition of those who were under the servitude of the Law. It would strikingly represent Mount Sinai, and the Law that was promulgated there, and the condition of those who were under the Law. That, too, was a condition of servitude. The Law was stern, and showed no mercy. It was like a master of a slave, and would treat those who were under it with a rigidness that might be compared with the condition of Hagar and her son; Galatians 4:24-25. That same Mount Sinai also was a fair representation of Jerusalem as it was then - a city full of rites and ceremonies, where the Law reigned with rigor, where, there was a burdensome system of religion, and where there was none of the freedom which the gospel would furnish; Galatians 4:25.
On the other hand, the children of the free woman were an apt illustration of those who were made free from the oppressive ceremonies of the Law by the gospel; Galatians 4:22. That Jerusalem was free. The new system from heaven was one of liberty and rejoicing; Galatians 4:26-27. Christians were, like Isaac, the children of promise, and were not slaves to the Law; Galatians 4:28, Galatians 4:31. And as there was a command Galatians 4:30 to east out the bondwoman and her son, so the command now was to reject all that would bring the mind into ignoble servitude, and prevent its enjoying the full freedom of the gospel. The whole argument is, that it would be as unreasonable for those who were Christians to submit again to the Jewish rites and ceremonies, as it would be for a freeman to sell himself into slavery. And the design of the whole is, to recall them from the conformity to Jewish rites and customs, and from their regarding them as now binding on Christians.

The apostle shows that, as an heir in nonage is under tutors and guardians, so were the Galatians while under the law; and, as the heir when he comes of age is no longer under guardians, so they, when the Gospel came, arrived at full maturity, and were redeemed from the law, Galatians 4:1-3. He shows, farther, that when the fullness of the time came God sent forth his Son, that we might obtain the adoption of sons, and have the strongest evidence of that adoption, Galatians 4:4-6. Those who are children of God are heirs of heaven, Galatians 4:7. He compares their former and latter state, and shows the reason he had to fear that his labor on their behalf was in vain, Galatians 4:8-11. He mentions his trials among them, and their kindness to him, Galatians 4:12-16. Shows his tender affection for them, and exhorts them to return to the Gospel, Galatians 4:17-20. Shows the excellence of the Gospel beyond that of the law, by the allegory of Mount Sinai and Jerusalem, Galatians 4:21-27. Shows also that the believing Gentiles are children of the promise, as Isaac was; and have been elected in the place of the Jews, who have been cast out according to the Scriptures, Galatians 4:28-31.

INTRODUCTION TO GALATIANS 4
In this chapter the apostle discourses concerning the abrogation of the ceremonial law, under which the Old Testament saints were, being as children under tutors; blames the Galatians for returning to it when they were freed from it; puts them in mind of their former affection to him and to his ministry; describes the false apostles, who had been the occasion of their departure from the truth, and by a beautiful allegory sets forth the difference between the legal and Gospel dispensations. And whereas in the latter part of the preceding chapter he had compared the law to a schoolmaster, under which the Jews were till Christ came; he here makes use of another simile to express the same thing by, which is that of an heir while under age being under tutors and governors, until the time fixed by the parent's will, Galatians 4:1 an accommodation of which simile is in Galatians 4:3, by which the Jews under the former dispensation are represented as children, and as in a state of bondage to the ceremonial law, from which there is a deliverance by Christ at the appointed time of the Father, by whom he was sent for that purpose; the act of sending is ascribed to God the Father; the person sent is described as the Son of God; the time when is called the fulness of time; and the circumstances under which he was sent were, that he was made of a woman, and made under the law, Galatians 4:4, the ends of his being sent were to redeem his people from it, who were under it; and that they might receive the adoption of children, the privilege and spirit of it, Galatians 4:5. Hence because they were the sons of God, and as a fruit and effect of the redemption of them by Christ, the Spirit of God is sent down into their hearts, to make known and witness their adoption, Galatians 4:6, and the benefits arising from hence are, that such are or should be no longer the servants of the law, but are children and free from it, and are heirs of God, Galatians 4:7, and that the grace of God might appear the more illustrious in this privilege of sonship, and the folly of the Galatians be more manifest in returning to the ceremonial law, notice is taken of what they were and did before conversion, and what they were inclined to now; that whereas whilst they were ignorant of God, they served nominal fictitious deities, such as were not by nature gods; and yet now, though they knew God, and were known of him, seemed desirous of being in a state of servitude and bondage to the weak and beggarly elements of the ceremonial law, Galatians 4:8, of which instances are given in their observing days, months, times and years, Galatians 4:10, which gave the apostle a great deal of concern, fearing his labour among them was in vain, and to no purpose, Galatians 4:11, wherefore he entreats them as his brethren to imitate him, who being a Jew, yet had relinquished the observation of the ceremonial law, Galatians 4:12, and then he reminds them of their former regard unto him; how that though he preached the Gospel to them through much weakness, yet they did not despise him and reject him on account of his infirmities, but received him with all the tokens of respect imaginable, as if he had been an angel; yea, as if he had been Christ himself, Galatians 4:13, who then reckoned themselves happy persons on account of the Gospel he preached to them, and then had such an affection for him, that if it had been needful they would have given their eyes unto him; and yet now he was become their enemy for preaching the same truths he did then, justification by faith in Christ's righteousness and the abrogation of the law, Galatians 4:15, next he gives an account of the false apostles, who pretended a zealous affection for the Galatians; which was not a good one, nor with right views, Galatians 4:17, though zeal in a good cause, and which continues, is very commendable, Galatians 4:18, and such a constant and hearty attachment had the apostle to them; wherefore he calls them his little children, says he travailed in birth on their account, it being his earnest desire that Christ might appear to be formed in them, Galatians 4:19, wherefore since he was in doubt and distress about them, he was very desirous of being with them, and to alter his way of arguing with them; and from the law, and not the Gospel, show them their mistake and folly, Galatians 4:20, which he does in the following allegorical way, by observing that Abraham had two sons, the one by a servant maid, the other by his lawful wife; the one was after the flesh, the other by promise; which allegorically signified the two covenants of Sinai and of Sion, Galatians 4:22. Agar the bondmaid represented the covenant made at Mount Sinai in Arabia, under which the carnal Jews and their posterity were in a state of bondage; and Sarah the free woman, the covenant of grace under the Gospel dispensation and the Gospel church state, which is from above, free, fertile, and numerous, Galatians 4:25, which is confirmed, Galatians 4:27, by a passage out of Isaiah 44:1 and as these two women were typical of the two covenants, so their respective offspring represented the two sorts of professors, legalists and evangelical Christians. True believers in Christ are like Isaac, the children of the promise; legalists are like Ishmael, men after the flesh, and of the same persecuting spirit with him: wherefore as it was then, that carnal Ishmael persecuted spiritual Isaac, so at this time the carnal Jews persecuted the real Christians, Galatians 4:28 nevertheless for the comfort of the latter, it is observed out of the Scripture that the former shall be cast out, and not be heir with them, Galatians 4:30, and the conclusion of the whole is, that the saints under the Gospel dispensation are not in bondage to the law, but are made free by Christ; to which freedom they are called, and in which they should stand, Galatians 4:31.

(Galatians 4:1-7) The folly of returning to legal observances for justification.
(Galatians 4:8-11) The happy change made in the Gentile believers.
(Galatians 4:12-18) The apostle reasons against following false teachers.
(Galatians 4:19, Galatians 4:20) He expresses his earnest concern for them.
(Galatians 4:21-31) And then explains the difference between what is to be expected from the law, and from the gospel.

SUMMARY.--Children, While Minors, Not Free. So the Israelites Under the Bondage of the Law Until Christ Came. Christ Frees From This Bondage. The Folly of Gentiles Seeking This Bondage. How the Galatians Had Once Welcomed the Gospel. The Two Covenants, Hagar, and Sarah, and Their Significance.