Brethren, I speak in the manner of men: Though it is only a man's covenant, yet if it is confirmed, no one annuls or adds to it.
Now to Abraham and his Seed were the promises made. He does not say, "And to seeds," as of many, but as of one, "And to your Seed," who is Christ.
References for Galatians 3:16
And this I say, that the law, which was four hundred and thirty years later, cannot annul the covenant that was confirmed before by God in Christ, that it should make the promise of no effect.
References for Galatians 3:17
For if the inheritance is of the law, it is no longer of promise; but God gave it to Abraham by promise.
What purpose then does the law serve? It was added because of transgressions, till the Seed should come to whom the promise was made; and it was appointed through angels by the hand of a mediator.
Now a mediator does not mediate for one only, but God is one.
Is the law then against the promises of God? Certainly not! For if there had been a law given which could have given life, truly righteousness would have been by the law.
But the Scripture has confined all under sin, that the promise by faith in Jesus Christ might be given to those who believe.
But before faith came, we were kept under guard by the law, kept for the faith which would afterward be revealed.
Therefore the law was our tutor to bring us to Christ, that we might be justified by faith.
But after faith has come, we are no longer under a tutor.