Romans 4:16-21

So the promise is received by faith. It is given as a free gift. And we are all certain to receive it, whether or not we live according to the law of Moses, if we have faith like Abraham’s. For Abraham is the father of all who believe. That is what the Scriptures mean when God told him, “I have made you the father of many nations.” This happened because Abraham believed in the God who brings the dead back to life and who creates new things out of nothing. Even when there was no reason for hope, Abraham kept hoping—believing that he would become the father of many nations. For God had said to him, “That’s how many descendants you will have!” And Abraham’s faith did not weaken, even though, at about 100 years of age, he figured his body was as good as dead—and so was Sarah’s womb. Abraham never wavered in believing God’s promise. In fact, his faith grew stronger, and in this he brought glory to God. He was fully convinced that God is able to do whatever he promises.