Romans 9:7

The first proposition of this verse has almost the same meaning as the second of Romans 9:6, but with a different shade intimated by the particle οὐδέ, neither further. The apostle, by way of transition to the following discussion, Romans 9:8-9, for the expression: which are of Israel, substitutes seed of Abraham. For he is going to speak of the lot of Abraham's two sons, Ishmael and Isaac. Both were seed of Abraham; but they did not both for that reason deserve the title of child. This term, taken absolutely, combines the characteristic of a child of Abraham with that of a child of God; for the subject in question is evidently that of the true members of God's family.

The simple fact of descending from Abraham is so far from making a man his child, in this exalted sense, that God, on the contrary, excludes from the divine family every other descendant of Abraham than Isaac and his seed, when He says to Abraham, Genesis 21:12 (literally): “In Isaac shall thy seed be called.” This last word evidently denotes the seed of Abraham properly so called, that which was to remain the depositary of the promise of salvation for the world. We might identify the person of Isaac with his seed, and understand the ἐν, in, in this sense: in the very person of Isaac (as containing in him all his descendants). The verb καλεῖν, to call, would be taken here, as in Romans 4:17, in the sense of: to call into existence. But as Isaac was already born, and as the verb kara refers rather to the name to be given, it is more natural to distinguish Isaac from the seed, to understand καλεῖσθαι in the sense of: to bear the name of, and to explain the ἐν in the sense of through: “By Isaac it is that the race shall be born who shall truly bear the name of seed. ”