Romans 9:10

10 And this is not all. For Rebecca's two sons had the same father, our ancestor Isaac.

Romans 9:10 Meaning and Commentary

Romans 9:10

And not only this
This instance of Ishmael and Isaac, is not the only one, proving that Abraham's natural seed, the children of the flesh, are not all children, the children of God:

but when Rebecca also had conceived by one, even by our father Isaac,
"it was said unto her", ( Romans 9:12 ) , being in a parenthesis, "the elder shall serve the younger". The apostle was aware, that the Jews would be ready to say, that the instance of Ishmael and Isaac was not a pertinent one; since Ishmael was not born of Sarah, the lawful wife of Abraham, but of a bondwoman, which was the reason his rejection, when Isaac was the son of promise, by the lawful wife, and that they were children of Abraham in the line of Isaac, and so children of the promise, as he was: wherefore he proceeds to mention the case of Jacob and Esau, which was not liable to any such exception; seeing they not only had the same father, but the same mother, Isaac's lawful wife; they were conceived by Rebecca at once, were in the same womb together, were twins, and if any had the preference and advantage, Esau had it, being born first; and yet a difference was made between these two by God himself, and which was notified by him to the mother of them, before either were born.

Romans 9:10 In-Context

8 This means that the children born in the usual way are not the children of God; instead, the children born as a result of God's promise are regarded as the true descendants.
9 For God's promise was made in these words: "At the right time I will come back, and Sarah will have a son."
10 And this is not all. For Rebecca's two sons had the same father, our ancestor Isaac.
11 But in order that the choice of one son might be completely the result of God's own purpose, God said to her, "The older will serve the younger." He said this before they were born, before they had done anything either good or bad; so God's choice was based on his call, and not on anything they had done.
Scripture taken from the Good News Translation - Second Edition, Copyright 1992 by American Bible Society. Used by Permission.