19 The purpose of the law was to keep a sinful people in the way of salvation until Christ (the descendant) came, inheriting the promises and distributing them to us. Obviously this law was not a firsthand encounter with God. It was arranged by angelic messengers through a middleman, Moses. 20 But if there is a middleman as there was at Sinai, then the people are not dealing directly with God, are they? But the original promise is the direct blessing of God, received by faith. 21 If such is the case, is the law, then, an anti-promise, a negation of God's will for us? Not at all. Its purpose was to make obvious to everyone that we are, in ourselves, out of right relationship with God, and therefore to show us the futility of devising some religious system for getting by our own efforts what we can only get by waiting in faith for God to complete his promise. For if any kind of rule-keeping had power to create life in us, we would certainly have gotten it by this time. 22
Matthew Henry's Commentary on Galatians 3:19-22
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.