Romans 9:6-8 KJV: Not as though the word of God hath taken none effect. For they are not all Israel, which are of Israel: [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.
Galatians 3:16 KJV: Now to Abraham and his seed were the promises made. He saith not, And to seeds, as of many; but as of one, And to thy seed, which is Christ.
Galatians 3:29 KJV: And if ye be Christ’s, then are ye Abraham’s seed, and heirs according to the promise.