In this chapter the apostle deals plainly with those who hearkened to the judaizing teachers, who cried up the law of Moses in competition with the gospel of Christ, and endeavored to bring them under the bondage of it. To convince them of their folly, and to rectify their mistake herein, in these verses he prosecutes the comparison of a child under age, which he had touched upon in the foregoing chapter, and thence shows what great advantages we have now, under the gospel, above what they had under the law. And here. I. He acquaints us with the state of the Old Testament church: it was like a child under age, and it was used accordingly, being kept in a state of darkness and bondage, in comparison of the greater light and liberty which we enjoy under the gospel. That was indeed a dispensation of grace, and yet it was comparatively a dispensation of darkness; for as the heir, in his minority, is under tutors and governors till the time appointed of his father, by whom he is educated and instructed in those things which at present he knows little of the meaning of, though afterwards they are likely to be of great use to him; so it was with the Old Testament church - the Mosaic economy, which they were under, was what they could not fully understand the meaning of; for, as the apostle says (Co2 3:13), They could not stedfastly look to the end of that which is abolished. But to the church, when grown up to maturity, in gospel days, it becomes of great use. And as that was a dispensation of darkness, so of bondage too; for they were in bondage under the elements of the world, being tied to a great number of burdensome rites and observances, by which, as by a kind of first rudiments, they were taught and instructed, and whereby they were kept in a state of subjection, like a child under tutors and governors. The church then lay more under the character of a servant, being obliged to do every thing according to the command of God, without being fully acquainted with the reason of it; but the service under the gospel appears to be more reasonable than that was. The time appointed of the Father having come, when the church was to arrive at its full age, the darkness and bondage under which it before lay are removed, and we are under a dispensation of greater light and liberty. II. He acquaints us with the much happier state of Christians under the gospel-dispensation, Gal 4:4-7. When the fulness of time had come, the time appointed of the Father, when he would put an end to the legal dispensation, and set up another and a better in the room of it, he sent forth his Son, etc. The person who was employed to introduce this new dispensation was no other than the Son of God himself, the only-begotten of the Father, who, as he had been prophesied of and promised from the foundation of the world, so in due time he was manifested for this purpose. He, in pursuance of the great design he had undertaken, submitted to be made of a woman - there is his incarnation; and to be made under the law - there is his subjection. He who was truly God for our sakes became man; and he who was Lord of all consented to come into a state of subjection and to take upon him the form of a servant; and one great end of all this was to redeem those that were under the law - to save us from that intolerable yoke and to appoint gospel ordinances more rational and easy. He had indeed something more and greater in his view, in coming into the world, than merely to deliver us from the bondage of the ceremonial law; for he came in our nature, and consented to suffer and die for us, that hereby he might redeem us from the wrath of God, and from the curse of the moral law, which, as sinners, we all lay under. But that was one end of it, and a mercy reserved to be bestowed at the time of his manifestation; then the more servile state of the church was to come to a period, and a better to succeed in the place of it; for he was sent to redeem us, that we might receive the adoption of sons - that we might no longer be accounted and treated as servants, but as sons grown up to maturity, who are allowed greater freedoms, and admitted to larger privileges, than while they were under tutors and governors. This the course of the apostle's argument leads us to take notice of, as one thing intended by this expression, though no doubt it may also be understood as signifying that gracious adoption which the gospel so often speaks of as the privilege of those who believe in Christ. Israel was God's son, his first-born, Rom 9:4. But now, under the gospel, particular believers receive the adoption; and, as an earnest and evidence of it, they have together therewith the Spirit of adoption, putting them upon the duty of prayer, and enabling them in prayer to eye God as a Father (Gal 4:6): Because you are sons, God hath sent forth the Spirit of his Son into your hearts, crying Abba, Father. And hereupon (Gal 4:7) the apostle concludes this argument by adding, Wherefore thou art no more a servant, but a son; and, if a son, then an heir of God through Christ; that is, Now, under the gospel state, we are no longer under the servitude of the law, but, upon our believing in Christ, become the sons of God; we are thereupon accepted of him, and adopted by him; and, being the sons, we are also heirs of God, and are entitled to the heavenly inheritance (as he also reasons Rom 8:17), and therefore it must needs be the greatest weakness and folly to turn back to the law, and to seek justification by the works of it. From what the apostle says in these verses, we may observe, 1. The wonders of divine love and mercy towards us, particularly of God the Father, in sending his Son into the world to redeem and save us, - of the Son of God, in submitting so low, and suffering so much, for us, in pursuance of that design, - and of the Holy Spirit, in condescending to dwell in the hearts of believers for such gracious purposes. 2. The great and invaluable advantages which Christians enjoy under the gospel; for, (1.) We receive the adoption of sons. Whence note, It is the great privilege which believers have through Christ that they are adopted children of the God of heaven. We who by nature are children of wrath and disobedience have become by grace children of love. (2.) We receive the Spirit of adoption. Note, [1.] All who have the privilege of adoption have the Spirit of adoption - all who are received into the number partake of the nature of the children of God; for he will have all his children to resemble him. [2.] The Spirit of adoption is always the Spirit of prayer, and it is our duty in prayer to eye God as a Father. Christ has taught us in prayer to eye God as our Father in heaven. [3.] If we are his sons, then his heirs. It is not so among men, with whom the eldest son is heir; but all God's children are heirs. Those who have the nature of sons shall have the inheritance of sons.