Neither because they are lineally the seed of Abraham, will it follow that they are all children of God — This did not hold even in Abraham's own family; and much less in his remote descendants. But God then said, In Isaac shall thy seed be called — That is, Isaac, not Ishmael, shall be called thy seed; that seed to which the promise is made.
Related Commentaries of Romans 9:7
Romans 9:7
7 Neither, because they are the seed of Abraham, are they all children: but, In Isaac shall thy seed be called.