Romans 4:17-18

17As it is written: “I have made you a father of many nations.” Gen. 17:5 He is our father in the sight of God, in whom he believed—the God who gives life to the dead and calls into being things that were not. 18Against all hope, Abraham in hope believed and so became the father of many nations, just as it had been said to him, “So shall your offspring be.” Gen. 15:5