Romans 9:7-9

King James Version

⁷ Neither, because they are the seed of Abraham, are they all children: but, In Isaac shall thy seed be called.

⁸ That is, They which are the children of the flesh, these are not the children of God: but the children of the promise are counted for the seed.

⁹ For this is the word of promise, At this time will I come, and Sarah shall have a son.