To Florus 2.109

Wisely, therefore, when speaking of Adam, he named one sin, which he intended to be understood as a model of transgression. He mentioned one, I repeat, and not many, because he knew that only one sin of Adam is recorded in the law’s history. But he praised grace for sending those it initiates out into justification from many offenses, to prevent any suspicion of a meager benefit. If he had said, ‘Grace is from one offense to justification,’ it might have seemed to abolish individual sins rather than all sins. Thus, by first mentioning one sin he remained faithful to the history; by adding, ‘Grace is from many offenses to justification,’ he commended the sacrament’s generosity and abundance (Romans 5:16).