Romans 9:6-8 - WEB
6
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
Neither, because they are Abraham`s seed, are they all children. But, "In Isaac will your seed be called."
8
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.
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