The promise of inheriting the world was not made to Abraham and his descendants on account of any law but on account of the righteousness which consists in faith. That is why what fulfils the promise depends on faith, so that it may be a free gift and be available to all of Abraham’s descendants, not only those who belong to the Law but also those who belong to the faith of Abraham who is the father of all of us. As scripture says: I have made you the ancestor of many nations – Abraham is our father in the eyes of God, in whom he put his faith, and who brings the dead to life and calls into being what does not exist.  

Though it seemed Abraham’s hope could not be fulfilled, he hoped and he believed, and through doing so he did become the father of many nations exactly as he had been promised: Your descendants will be as many as the stars. This is the faith that was ‘considered as justifying him.’