Galatians 3:19-22 meaning

Paul says that the law was given because of the sinfulness of man to guide them until Christ came, until the seed (Jesus) would come to whom the promise was made. The law is not life-giving like the promise of God acquired through faith.

The Law was given by the agency of a mediator. This appears to be a validation of the belief the Jews had that angels were messengers that gave the Law to the people of Israel. Hebrews 2:2 appears to make the same point. But a mediator is not for one party only. There has to be at least two parties for a mediator to function. The Law was given through a mediator, from God to man. But God gave His promise to Abraham directly. God is only one. So the promise of God to Abraham must be something completely different from the Law.

It is important to recall that the entire letter to the Galatians is to straighten out their understanding, which has been warped by competing Jewish "authorities" who claim it is necessary to keep religious rules in order to be completed in Christ (Galatians 3:3) and even to be justified in the presence of God (Galatians 2:2). The law does not save or complete anyone. It does however show our need for Jesus. The Scripture has shut up everyone under sin, so that the promise by faith in Jesus Christ might be given to those who believe.