3:16. To Abraham were the promises made and to his seed. He saith not: And to his seeds as of many. But as of one: And to thy seed, which is Christ.
3:17. Now this I say: that the testament which was confirmed by God, the law which was made after four hundred and thirty years doth not disannul, to make the promise of no effect.
3:18. For if the inheritance be of the law, it is no more of promise. But God gave it to Abraham by promise.
3:19. Why then was the law? It was set because of transgressions, until the seed should come to whom he made the promise, being ordained by angels in the hand of a mediator.
Because of transgressions… To restrain them from sin, by fear and threats. Ordained by angels… The law was delivered by angels, speaking in the name and person of God to Moses, who was the mediator, on this occasion, between God and the people.
3:20. Now a mediator is not of one: but God is one.
3:21. Was the law then against the promises of God: God forbid! For if there had been a law given which could give life, verily justice should have been by the law.
3:22. But the scripture hath concluded all under sin, that the promise, by the faith of Jesus Christ, might be given to them that believe.
Hath concluded all under sin… that is, hath declared all to be under sin, from which they could not be delivered but by faith in Jesus Christ, the promised seed.
3:23. But before the faith came, we were kept under the law shut up, unto that faith which was to be revealed.