Romans 4:17-19

As it is written in the Scriptures: “I am making you a father of many nations.” This is true before God, the God Abraham believed, the God who gives life to the dead and who creates something out of nothing. There was no hope that Abraham would have children. But Abraham believed God and continued hoping, and so he became the father of many nations. As God told him, “Your descendants also will be too many to count.” Abraham was almost a hundred years old, much past the age for having children, and Sarah could not have children. Abraham thought about all this, but his faith in God did not become weak.