Romans 4:18-22

Abraham believed and hoped, even when there was no reason for hoping, and so became “the father of many nations.” Just as the scripture says, “Your descendants will be as many as the stars.” He was then almost 100 years old; but his faith did not weaken when he thought of his body, which was already practically dead, or of the fact that Sarah could not have children. His faith did not leave him, and he did not doubt God's promise; his faith filled him with power, and he gave praise to God. He was absolutely sure that God would be able to do what he had promised. That is why Abraham, through faith, “was accepted as righteous by God”.