Galatians 3:17-19

17And this I say, that the covenant, that was confirmed before by God in Christ, the law, which was four hundred and thirty years after, cannot set it aside, that it should make the promise of no effect. 18For if the inheritance is by the law, it is no more by promise: but God gave it to Abraham by promise.

19What purpose thenserveth the law? It was added because of transgressions, till the seed should come to whom the promise was made; and it was ordained by angels in the hand of a mediator.