THE COVENANT THAT CANNOT BE ALTERED (Galatians 3:15-18)
3:15-18 Brothers, I can use only a human analogy. Here is the parallel when a covenant is duly ratified, even if it is only a man's covenant, no one annuls it or adds additional clauses to it. Now the promises were made to Abraham and to his seed. It does not say, "and to his seeds," as if it were a case of many, but, "and to his seed," as if it were a case of one, and that one is Christ. This is what I mean, the law which came into being four hundred and thirty years later cannot annul the covenant already ratified by God and thus render the promise inoperative. For. if the inheritance is dependent on law, it is no longer dependent on promise; but it was through promise that God conferred his grace on Abraham.
When we read passages like this and the next one, we have to remember that Paul was a trained Rabbi, an expert in the scholastic methods of the Rabbinic academies. He could, and did, use their methods of argument, which would be completely cogent to a Jew, however difficult it may be for us to understand them.
His aim is to show the superiority of the way of grace over the way of law. He begins by showing that the way of grace is older than the way of law. When Abraham made his venture of faith, God made his great promise to him. That is to say. God's promise was consequent upon an act of faith; the law did not come until the time of Moses, four hundred and thirty years later. But--Paul goes on to argue--once a covenant has been duly ratified, you cannot alter it nor add additional clauses to it. Therefore, the later law cannot alter the earlier way of faith. It was faith which set Abraham right with God; and faith is still the only way for a man to get himself right with God.
The Rabbis were very fond of using arguments which depended on the interpretation of single words; they would erect a whole theology on one word. Paul takes one word in the Abraham story and erects an argument upon it. As the King James Version translates Genesis 17:7-8, God says to Abraham, "I will establish my covenant between me and thee and thy seed after thee" and says of his inheritance, "I will give it unto thee and to thy seed after thee." (Seed is more clearly rendered descendant, as the Revised Standard Version has it.) Paul's argument is that seed is used in the singular and not in the plural; and that, therefore, God's promise points not to a great crowd of people but to one single individual; and--argues Paul--the one person in whom the covenant finds its consummation is Jesus Christ. Therefore, the way to peace with God is the way of faith which Abraham took; and we must repeat that way by looking to Jesus Christ in faith.
Again and again Paul comes back to the same point. The problem of human life is to get into a right relationship with God. So long as we are afraid of him, there can be no peace. How are we to achieve this right relationship? Shall it be by a meticulous and even self-torturing obedience to the law, by performing endless deeds and observing every smallest regulation the law lays down? If we take that way we will be forever in default, for man's imperfection can never fully satisfy God's perfection; but if we abandon this hopeless struggle and bring ourselves and our sin to God, his grace opens its arms to us and we find ourselves at peace with a God who is no longer judge but father. Paul's argument is that this is what happened to Abraham. It was on that basis that God's covenant with Abraham was made; and nothing that came in later can change that covenant any more than anything can alter a will that has already been ratified and signed.