Galatians 3:16-20

God gave the promises to Abraham and his child. And notice that the Scripture doesn’t say “to his children,” as if it meant many descendants. Rather, it says “to his child”—and that, of course, means Christ. This is what I am trying to say: The agreement God made with Abraham could not be canceled 430 years later when God gave the law to Moses. God would be breaking his promise. For if the inheritance could be received by keeping the law, then it would not be the result of accepting God’s promise. But God graciously gave it to Abraham as a promise. Why, then, was the law given? It was given alongside the promise to show people their sins. But the law was designed to last only until the coming of the child who was promised. God gave his law through angels to Moses, who was the mediator between God and the people. Now a mediator is helpful if more than one party must reach an agreement. But God, who is one, did not use a mediator when he gave his promise to Abraham.