Commentaries:
In Matthew 3:9 and Luke 3:8, John the Baptist tells the Jews gathered to hear him not to think that they had it made because they were sons of Abraham, for God can raise children up out of the very stones. In John 8, Jesus encountered the same argument from the Jews, and He said, "Don't think because you are descendants of Abraham that you are Abraham's heirs. He never did the things that you're doing. You want to kill me. Your father is Satan the Devil, not Abraham" (see John 8:37-44).
What we see in Romans 9 is a much bolder and clearer explanation of the same pattern. Paul is explaining what God has been doing all this time and why He will continue to work through Israel. He is not all that concerned about the physical nation. Perhaps He is to some degree, but only because within the physical nation He established through Abraham, Isaac, and Jacob is the real Israel.
John W. Ritenbaugh
The Covenants, Grace, and Law (Part Eleven)
"The children of the promise are counted for the seed" means Abraham's seed, and "the children" are Esau and Jacob. Jacob was chosen or elected by God, but Esau was not. So through whom would God work? Obviously, it was Jacob, who on the surface was the weaker of the two—perhaps in character and certainly bodily. The question immediately arises, "Is it fair of God to do this?"
John W. Ritenbaugh
The Covenants, Grace, and Law (Part Eleven)
Other Forerunner Commentary entries containing Romans 9:7:
Genesis 21:12
Genesis 35:10-11
Genesis 35:10-11
Genesis 48:16
Matthew 10:5-7
Luke 16:22
John 3:7
Galatians 4:24-26