Galatians 3:17-19, 23-25

This means that the covenant between God and Abraham was fulfilled in Messiah and cannot be altered. Yet the written law was not even given to Moses until 430 years after God had “signed” his contract with Abraham! The law, then, doesn’t supersede the promise since the royal proclamation was given before the law. If that were the case, it would have nullified what God said to Abraham. We receive all the promises because of the Promised One—not because we keep the law! Why then was the law given at all? It was given alongside the promise to show people their sins. But the law was designed to last only until the coming of the “Seed,” the child who was promised. When God gave the law, he gave it first to angels; they gave it to Moses, his mediator, who then gave it to the people.

So until the revelation of faith for salvation was released, the law was a jailer, holding us as prisoners under lock and key until the “faith,” which was destined to be revealed, would set us free. The law was our guardian until Christ came so that we would be saved by faith. But now that faith has come we are no longer under the guardian of the law.