That is, Not the children, &c. — As if he had said, This is a clear type of things to come; showing us, that in all succeeding generations, not the children of the flesh, the lineal descendants of Abraham, but the children of the promise, they to whom the promise is made, that is, believers, are the children of God. Genesis 21:12
Related Commentaries of Romans 9:8
Romans 9:8
8 That is, They which are the children of the flesh, these are not the children of God: but the children of the promise are counted for the seed.