15-18Friends, let me give you an example from everyday affairs of the free life I am talking about. Once a person's will has been ratified, no one else can annul it or add to it. Now, the promises were made to Abraham and to his descendant. You will observe that Scripture, in the careful language of a legal document, does not say "to descendants," referring to everybody in general, but "to your descendant" (the noun, note, is singular), referring to Christ. This is the way I interpret this: A will, earlier ratified by God, is not annulled by an addendum attached 430 years later, thereby negating the promise of the will. No, this addendum, with its instructions and regulations, has nothing to do with the promised inheritance in the will.
18-20What is the point, then, of the law, the attached addendum? It was a thoughtful addition to the original covenant promises made to Abraham. The purpose of the law was to keep a sinful people in the way of salvation until Christ (the descendant) came, inheriting the promises and distributing them to us. Obviously this law was not a firsthand encounter with God. It was arranged by angelic messengers through a middleman, Moses. But if there is a middleman as there was at Sinai, then the people are not dealing directly with God, are they? But the original promise is the direct blessing of God, received by faith.