16 That is why it depends on faith, in order that the promise may rest on grace and be guaranteed to all his descendants—not only to the adherents of the law but also to those who share the faith of Abraham, for he is the father of us all, 17 as 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.