Romans 4:16-18

16Therefore, the promise comes by faith, so that it may rest on grace and may be guaranteed to all Abraham’s offspring—not only to those who are of the law, but also to those who are of the faith of Abraham. He is the father of us all. 17As it is written: “I have made you a father of many nations.”1 He is our father in the presence of God, in whom he believed, the God who gives life to the dead and calls into being what does not yet exist.

18Against all hope, Abraham in hope believed and so became the father of many nations, just as he had been told, “So shall your offspring be.”2