Romans 9
6 Ref But it is not as though the word of God has come to nothing. For they are not all Israel, that are of Israel.
7 Ref Neither, because they are Abraham's seed, are they all children. But, "In Isaac will your seed be called."
8 Ref That is, it is not the children of the flesh who are children of God, but the children of the promise are counted as a seed.