To Florus 2.153

‘For the promise to Abraham that he would be heir of the world came not through the law but through the righteousness of faith. If those who are of the law are heirs, faith is emptied and the promise destroyed. For the law produces wrath; but where there is no law, neither is there transgression. Therefore it comes from faith, so that according to grace the promise may be secure for all the offspring—not only those who are of the law, but also those who are of Abraham’s faith. He is the father of us all, as it is written: “I have made you the father of many nations,” before the God whom he believed, who gives life to the dead and calls the things that do not exist as though they exist. Beyond hope, he believed in hope, so that he might become the father of many nations, according to what was said: “So shall your offspring be.” Without becoming weak in faith, he considered his own body, already dead, since he was nearly a hundred years old, and Sarah’s dead womb. Yet he did not hesitate in distrust over God’s promise, but was strengthened in faith, giving glory to God and knowing most fully that God is also able to do whatever he has promised. For this reason it was also reckoned to him as righteousness’ (Romans 4:13–22; embedded quotations from Genesis 17:5 and Genesis 15:5–6).