That is to say, not they that are the children of the flesh, are the children of God; but they, that are the children of the promise, are accounted for the seed.
And think not to say within yourselves, We have Abraham for our father. For I tell you that God is able of these stones to raise up children to Abraham.
By faith also Sara herself, being barren, received strength to conceive seed, even past the time of age; because she believed that he was faithful who had promised,