Romans 9:10

And not only this Here a still stronger example of sovereign choice occurs. Isaac and Ishmael had only one parent in common; Jacob and Esau had both. In the former case, the choice of Isaac was declared only after Ishmael's birth and childhood; in the latter, the choice of Jacob was declared while both brothers were in the womb. The Greek construction in Romans 9:10-12 is irregular, but perfectly clear.

by one In contrast to the divided parentageof Abraham's sons.

our father Isaac Here named with emphasis, as shewing that even within the inner circle of promise ("In Isaacshall thy seed, &c.,") there was still an election.