17 Now this I say: The law, which came four hundred and thirty years after, does not put an end to the agreement made before by God, so as to make the undertaking without effect. 18 Because if the heritage is by the law, it is no longer dependent on the word of God; but God gave it to Abraham by his word.

The Purpose of the Law

19 What then is the law? It was an addition made because of sin, till the coming of the seed to whom the undertaking had been given; and it was ordered through angels by the hand of a go-between. 20 Now a go-between is not a go-between of one; but God is one. 21 Is the law then against the words of God? in no way; because if there had been a law which was able to give life, truly righteousness would have been by the law. 22 However, the holy Writings have put all things under sin, so that that for which God gave the undertaking, based on faith in Jesus Christ, might be given to those who have such faith. 23 But before faith came, we were kept in prison under the law, waiting for the revelation of the faith which was to come. 24 So the law has been a servant to take us to Christ, so that we might have righteousness by faith.

Matthew Henry's Commentary on Galatians 3:17-24

Commentary on Galatians 3:15-18

(Read Galatians 3:15-18)

The covenant God made with Abraham, was not done away by the giving the law to Moses. The covenant was made with Abraham and his Seed. It is still in force; Christ abideth for ever in his person, and his spiritual seed, who are his by faith. By this we learn the difference between the promises of the law and those of the gospel. The promises of the law are made to the person of every man; the promises of the gospel are first made to Christ, then by him to those who are by faith ingrafted into Christ. Rightly to divide the word of truth, a great difference must be put between the promise and the law, as to the inward affections, and the whole practice of life. When the promise is mingled with the law, it is made nothing but the law. Let Christ be always before our eyes, as a sure argument for the defence of faith, against dependence on human righteousness.

Commentary on Galatians 3:19-22

(Read Galatians 3:19-22)

If that promise was enough for salvation, wherefore then serveth the law? The Israelites, though chosen to be God's peculiar people, were sinners as well as others. The law was not intended to discover a way of justification, different from that made known by the promise, but to lead men to see their need of the promise, by showing the sinfulness of sin, and to point to Christ, through whom alone they could be pardoned and justified. The promise was given by God himself; the law was given by the ministry of angels, and the hand of a mediator, even Moses. Hence the law could not be designed to set aside the promise. A mediator, as the very term signifies, is a friend that comes between two parties, and is not to act merely with and for one of them. The great design of the law was, that the promise by faith of Jesus Christ, might be given to those that believe; that, being convinced of their guilt, and the insufficiency of the law to effect a righteousness for them, they might be persuaded to believe on Christ, and so obtain the benefit of the promise. And it is not possible that the holy, just, and good law of God, the standard of duty to all, should be contrary to the gospel of Christ. It tends every way to promote it.

Commentary on Galatians 3:23-25

(Read Galatians 3:23-25)

The law did not teach a living, saving knowledge; but, by its rites and ceremonies, especially by its sacrifices, it pointed to Christ, that they might be justified by faith. And thus it was, as the word properly signifies, a servant, to lead to Christ, as children are led to school by servants who have the care of them, that they might be more fully taught by Him the true way of justification and salvation, which is only by faith in Christ. And the vastly greater advantage of the gospel state is shown, under which we enjoy a clearer discovery of Divine grace and mercy than the Jews of old. Most men continue shut up as in a dark dungeon, in love with their sins, being blinded and lulled asleep by Satan, through wordly pleasures, interests, and pursuits. But the awakened sinner discovers his dreadful condition. Then he feels that the mercy and grace of God form his only hope. And the terrors of the law are often used by the convincing Spirit, to show the sinner his need of Christ, to bring him to rely on his sufferings and merits, that he may be justified by faith. Then the law, by the teaching of the Holy Spirit, becomes his loved rule of duty, and his standard for daily self-examination. In this use of it he learns to depend more simply on the Saviour.