15 Brethren, I speak in terms of human relations: even though it is only a man’s covenant, yet when it has been ratified, no one sets it aside or adds conditions to it.16 Now the promises were spoken to Abraham and to his seed. He does not say, “And to seeds,” as referring to many, but rather to one, “And to your seed,” that is, Christ.17 What I am saying is this: the Law, which came four hundred and thirty years later, does not invalidate a covenant previously ratified by God, so as to nullify the promise.18 For if the inheritance is based on law, it is no longer based on a promise; but God has granted it to Abraham by means of a promise.
19 Why the Law then? It was added because of transgressions, having been ordained through angels by the agency of a mediator, until the seed should come to whom the promise had been made.20 Now a mediator is not for one party only; whereas God is only one.21 Is the Law then contrary to the promises of God? May it never be! For if a law had been given which was able to impart life, then righteousness would indeed have been based on law.22 But the Scripture has shut up all men under sin, that the promise by faith in Jesus Christ might be given to those who believe.