Romans 4:16-18
4:16 For this reason it is by faith so that it may be by grace, with the result that the promise may be certain to all the descendants – not only to those who are under the law, but also to those who have the faith of Abraham, who is the father of us all
4:17 (as it is written, “I have made you the father of many nations”). He is our father in the presence of God whom he believed – the God who makes the dead alive and summons the things that do not yet exist as though they already do.
4:18 Against hope Abraham believed in hope with the result that he became the father of many nations according to the pronouncement, “so will your descendants be.”