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.
22. But—as the law cannot give life or righteousness [Alford]. Or the "But" means, So far is righteousness from being of the law, that the knowledge of sin is rather what comes of the law [Bengel].
the scripture—which began to be written after the time of the promise, at the time when the law was given. The written letter was needed SO as PERMANENTLY to convict man of disobedience to God's command. Therefore he says, "the Scripture," not the "Law." Compare Ga 3:8, "Scripture," for "the God of the Scripture."
concluded—"shut up," under condemnation, as in a prison. Compare Isa 24:22, "As prisoners gathered in the pit and shut up in the prison." Beautifully contrasted with "the liberty wherewith Christ makes free," which follows, Ga 3:7, 9, 25, 26; 5:1; Isa 61:1.
all—Greek neuter, "the universe of things": the whole world, man, and all that appertains to him.
under sin—(Ro 3:9, 19; 11:32).
the promise—the inheritance promised (Ga 3:18).
by faith of Jesus Christ—that is which is by faith in Jesus Christ.
might be given—The emphasis is on "given": that it might be a free gift; not something earned by the works of the law (Ro 6:23).
to them that believe—to them that have "the faith of (in) Jesus Christ" just spoken of.