In Galatians 3:19, the Apostle Paul raised the question, “Wherefore then serveth the law?” in anticipation of the likely reaction by some to what he had asserted in verses 15-18. Starting with verse 15, he spoke about a covenant and how it was made binding on those who enter into agreement by the making of an oath. Once a covenant was made legally binding, it could not be disannulled and no further stipulations could be added to or taken from it. The Apostle established a principle in Hebrews 6:16 that, “An oath for confirmation is...an end of all strife.” In Gal. 3:16, he applied this same principle. God made promises to Abraham and He confirmed those promises with an oath, “Surely blessing I will bless thee, and multiplying I will multiply thee.”

The Apostle stressed that the seed of Abraham was singular and that it was one person: the Messiah, Jesus Christ our Lord. Therefore, the promises that God made to Abraham were also made to Jesus Christ, the Seed of Abraham. God ratified the covenant 430 years before the giving of the Law to Moses; therefore, the Law cannot invalidate the promise that God had long before made. In this, we see the superiority of the covenant of promise to the law of works. The covenant cannot be broken or undone by the law, and thus not even by the people’s transgression of that law.

Those who sought justification by the deeds of the law would certainly wonder, “If you are right, Paul, then what purpose serves the law?” In answer, the Apostle stated that God gave the Law to mark out transgressions and that it “was added…until the seed should come to whom the promise was made.” God meant for the Mosaic Law to be in force only up until the time when Jesus Christ, the promised seed, should come into the world.

In its several precepts, ordinances, and ceremonies, the Law contained an oracular view of the coming Messiah; the seed to whom God made the promises. The Law had a purpose but its purpose was not the same as the covenant’s purpose. The Law revealed sin. It demanded perfection. It required justice. It could never make anyone righteous. It could not empower anyone to keep its precepts. It constantly reminded the guilty of their cursed condition. By contrast, the covenant revealed righteousness. It assured justification to all embraced within it. God made the keeping and fulfilling of it binding on himself, and, as such, it gave true hope to its beneficiaries. It threatened no curse. It had its start in the great covenant made before the world began and it is never ending.

The apostle then explained the great difference between the giving of the one to the giving of the other. The Mosaic Law was "ordained" meaning it was put into effect, administered, set in order, arranged, and laid down. Verse 20 essentially confirmed what the Apostle said in verse 19. It was as if he had said, “The Law was ordained through a mediator. Now a mediator proves that more than one party was involved in the giving of the Law, but God was the only one involved in the making of the Covenant. God gave the Law to Moses through His celestial angels. This view finds support in two New Testament passages. One is Acts 7:53, "Who have received the law by the disposition of angels, and have not kept it." The other is Hebrews 2:2, "For if the word spoken by angels was stedfast, and every transgression and disobedience received a just recompence of reward."

The Apostle’s major point of emphasis in this section of his epistle has been to prove to the erring Galatians that a big difference existed between the promise and the Law; especially, between the making of the promise and the giving of the Law. God directly communicated an unconditional promise which He made binding on Himself unlike the Law which was a mediated requirement of behavior. There were no mediators or agents involved in the promise, and no curse (nor possibility of a curse) was attached to the promise like it was to the Law.

By the time the Apostle Paul has come to the end of the third chapter, he will have proved that in every significant way that mattered, the Law was not ever going to compare favorably to the Promise. The promise God made to Abraham pointed to the great covenant of grace that God made before the world began. The Promise was to be fulfilled in the appearance of His Son, Jesus Christ our Lord, the One True Seed of Abraham. In Christ Jesus are “all the nations of the earth blessed.” He is the Promised Seed in whom we are accounted as “Abraham’s seed and heirs according to the promise.”