in order that the blessing of Abraham might come to the Gentiles in Christ Jesus, so that we might receive the promise of the Spirit through faith.
Brothers, I am speaking according to a human perspective. Nevertheless, [when] the covenant of a man has been ratified, no one declares [it] invalid or adds additional provisions [to it].
References for Galatians 3:15
Now to Abraham and to his descendant the promises were spoken. It does not say, "and to descendants," as concerning many, but as concerning one, "and to your descendant," who is Christ.
References for Galatians 3:16
Now I am saying this: the law, that came after four hundred and thirty years, does not revoke a covenant previously ratified by God, in order to nullify the promise.
For if the inheritance [is] from the law, [it is] no longer from the promise, but God graciously gave [it] to Abraham through the promise.
Why then the law? It was added on account of transgressions, until the descendant should come to whom it had been promised, having been ordered through angels by the hand of a mediator.
References for Galatians 3:19
Now the mediator is not for one, but God is one.
Therefore [is] the law opposed to the promises of God? May it never be! For if a law had been given that was able to give life, certainly righteousness would have been from the law.
But the scripture imprisoned all under sin, in order that the promise could be given by faith in Jesus Christ to those who believe.
References for Galatians 3:22
But before faith came, we were detained under the law, imprisoned until the coming faith was revealed.
So then, the law became our guardian until Christ, in order that we could be justified by faith.