15 Dear brothers and sisters, here's an example from everyday life. Just as no one can set aside or amend an irrevocable agreement, so it is in this case. 16 God gave the promises to Abraham and his child. And notice that the Scripture doesn't say "to his children, " as if it meant many descendants. Rather, it says "to his child"-and that, of course, means Christ. 17 This is what I am trying to say: The agreement God made with Abraham could not be canceled 430 years later when God gave the law to Moses. God would be breaking his promise. 18 For if the inheritance could be received by keeping the law, then it would not be the result of accepting God's promise. But God graciously gave it to Abraham as a promise.

The Purpose of the Law

19 Why, then, was the law given? It was given alongside the promise to show people their sins. But the law was designed to last only until the coming of the child who was promised. God gave his law through angels to Moses, who was the mediator between God and the people. 20 Now a mediator is helpful if more than one party must reach an agreement. But God, who is one, did not use a mediator when he gave his promise to Abraham. 21 Is there a conflict, then, between God's law and God's promises? Absolutely not! If the law could give us new life, we could be made right with God by obeying it. 22 But the Scriptures declare that we are all prisoners of sin, so we receive God's promise of freedom only by believing in Jesus Christ.

Matthew Henry's Commentary on Galatians 3:15-22

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.