Paul carefully examines the terms of the Abrahamic covenant and notes that the promises of this covenant were made to Abraham and to his seed. The term seed, Paul explains, is not plural but singular. Therefore the covenant designated one person, not many people, to be the recipient of the promises. That one person, says Paul, is Christ.

Except for the lawyers among us who enjoy the minutiae of legal arguments, Paul's discussion may seem to be over our heads. But if we understand Paul's hidden agenda, we will be able to grasp the reason for this technical argument about one term in the Abrahamic covenant. We have to realize that Paul's definition of seed contradicts the Jewish nationalistic interpretation of this term. Jews were convinced that the term seed referred to the physical descendants of Abraham, the Jewish people. Therefore they believed it was absolutely necessary to belong to the Jewish nation in order to receive the blessings promised to Abraham.

In Jewish literature the generic singular seed was usually interpreted as a collective singular, referring to the nation of Israel. But seed was also understood by the rabbis to be a specific singular, referring to an individual—for example, Isaac or David or Solomon. Paul's attention to the grammatical form of this term is very much like the rabbinic practice of exegesis. But Paul's interpretation is based on his conviction that Christ is the sole heir and channel of God's promised blessing. So while he uses common Jewish methods of exegesis, Paul's messianic interpretation of seed restricts the reference to Christ and negates the common nationalistic interpretation. It is no longer necessary to be in the Jewish nation to be a recipient of the promises; it is necessary to be in Christ.

Paul is just as exclusive as his Jewish counterparts, but his exclusivity is not based on ethnic identity. Since Christ is the heir of the promises, all those and only those who are in Christ by faith are beneficiaries of the irrevocable trust agreement God made with Abraham (v. 29).

We can see by the way Paul uses the term seed in verse 29 that his emphasis on its singularity in verse 16 does not restrict the seed to one individual person. Christ, the one seed of Abraham, includes within himself a new community of all believers where there are no racial, social or gender divisions. Just as the seed is one (v. 16), so "you are all one in Christ" (v. 28). So the emphasis on the oneness of the seed in verse 16 prepares the way for the emphasis on the unity of all in Christ in verse 28. Whereas the law made a division between Jews and Gentiles, Christ, the promised seed of Abraham, is the center of a new unity of Jews and Gentiles. The people of God are no longer identified by ethnic origins, but by union with Christ.