Galatians 3:17-19

17What I mean is this: God made an agreement with Abraham. He promised to bless him. Then, 430 years later, God gave his Law to Moses for the Jewish people. But that Law could not take away the authority of God's agreement with Abraham. It could not stop what God had already promised.

18God has promised to give good things to his children. But that does not happen as a result of God's Law. If that were true, then we would not receive God's good things as a result of his promise. But God gave those good things to Abraham as a gift, because he had promised to bless Abraham.

19So we could ask: Why did God give his Law to his people after his promise to Abraham? He gave his Law to show them which things are wrong. It would have authority until Abraham's special descendant would come. That was the descendant that God had promised to bless. God used angels to give his Law to his people. It was Moses who received the Law from God, and Moses then took it to God's people.