Romans 4:16-21

16That is why it depends on faith, in order that the promise may rest on grace and be guaranteed to all his offspring—not only to the adherent of the law but also to the one who shares the faith of Abraham, who is the father of us all, 17as it is written, “I have made you the father of many nations”—in the presence of the God in whom he believed, who gives life to the dead and calls into existence the things that do not exist. 18In hope he believed against hope, that he should become the father of many nations, as he had been told, “So shall your offspring be.” 19He did not weaken in faith when he considered his own body, which was as good as dead (since he was about a hundred years old), or when he considered the barrenness of Sarah’s womb. 20No unbelief made him waver concerning the promise of God, but he grew strong in his faith as he gave glory to God, 21fully convinced that God was able to do what he had promised.