Romans 4:17-19

As it is written: “I have made you a father of many nations.” 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. Against 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.” Without weakening in his faith, he faced the fact that his body was as good as dead—since he was about a hundred years old—and that Sarah’s womb was also dead.