How did God make His covenant with man? The next verse says, "But to Abraham were the promises spoken and to his seed" (v. 16). God covenanted with Abraham through promises because it concerned the future. What is already accomplished is grace; what is not yet accomplished can only be a promise. Because the Lord Jesus had not yet come, we cannot say that God's covenant with Abraham was grace. Its nature was indeed grace, but because it had not been manifested, it was still a promise. This promise was given to Abraham and to his seed. Paul says, "He does not say, 'And to the seeds,' as concerning many, but as concerning one: 'And to your seed,' who is Christ" (v. 16). The seed is singular, not plural; it is one, Christ. God promised Abraham that he would bring forth Christ and that through Christ the nations would be blessed. Verse 14 says, "In order that the blessing of Abraham might come to the Gentiles in Christ Jesus, that we might receive the promise of the Spirit through faith." This is the covenant God made with Abraham.

Since God wants to bless the nations through Christ Jesus, why did He give man the law four hundred and thirty years later? Since the covenant God made with Abraham could not be annulled or supplemented, why would not the Lord Jesus just come to give us grace? Why did the problem of the law intervene? You have to see the argument Paul was making here. Paul was explaining why after four hundred and thirty years the law came in. Verse 17 says, "And I say this: A covenant previously ratified by God, the law, having come four hundred and thirty years after, does not annul so as to make the promise of none effect." Although God gave the law to man, the covenant He made four hundred and thirty years before could not be made of none effect. God could not cancel the covenant formerly made after some further thought four hundred and thirty years later. The law is something absolutely contradictory to promise and grace. What is a promise? It is something given to someone freely. Although he may not have it yet, he will definitely have it later. But what is the law? The law implies that one has to do this or that in order to get something. You can see that these two things are completely opposite. The promise implies that God will do something for man; the law implies that man will do something for God.

Verse 18 says, "For if the inheritance is of law, it is no longer of promise." If what was to be given is according to the principle of the law, it cannot be according to the principle of promise. These two things are completely opposite.

Verse 19 says, "Why then the law?" Now the problem arises; here we have the problem. This is a most difficult problem to solve. The law and the promise are basically contradictory in their natures. If you have the law, you cannot have the promise; if you have the promise, you cannot have the law. These two matters cannot stand together. But now there is the law, and there is also the promise. God gave the promise, and then four hundred and thirty years later He gave the law. What should you do? If the covenant made by God could not be changed, either by subtracting from it or by adding to it, why then was the law given? Since a covenant cannot be changed, a promise will always be a promise, and grace will always be grace. Why then is there the need for the law?