To Florus 2.160

But since you confess that transgressors under the law are not heirs of the blessing, because for such people the law produces wrath (Romans 4:15), it is clear that the promise concerns faith, not circumcision. The promise would be destroyed if no one were righteous apart from the law. For the law, introduced four hundred and thirty years after the promise (Galatians 3:17), would show Abraham himself, Isaac, Jacob, and all the holy people in between excluded from a blessing which could not have been conferred on anyone without the law.