Romans 8:16-17; Romans 8:21; Romans 9:7-8
The Spirit itself beareth witness with our spirit, that we are the children of God:
And if children, then heirs; heirs of God , and joint-heirs with Christ; if so be that we suffer with him, that we may be also glorified together .
Because the creature itself also shall be delivered from the bondage of corruption into the glorious liberty of the children of God.
Neither, because they are the seed of Abraham, are they all children: but, In Isaac shall thy seed be called .
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.