To Florus 2.56

The apostle showed that he was not saying sin passed on by generation when, naming a human being, he added ‘one.’ One is the beginning of number. Explaining through whom he said sin had entered, he not only named him but also counted him: ‘Through one man sin entered this world’ (Romans 5:12). This one person is sufficient to supply an example for imitation but insufficient to accomplish generation. Sin passed on, but through one. Clearly, then, what is accused here is imitation, not generation, which cannot take place except through two. Either show that generation occurred through Adam alone, without a woman—that would hardly be inconsistent with the refinement of your mind—or else, since you see that generation cannot exist without two, agree at last that the work of two was not accused by the number one. ‘Through one man,’ he says, ‘sin entered the world.’ In saying ‘through one,’ he did not mean us to understand ‘through two.’ Why, I ask, was number brought into these teachings, so that the apostle took such care to name not merely a human being but one human being? We see here the careful language of a lofty purpose: through the Holy Spirit’s revelation it anticipated and disarmed the errors of our times. When the subject required him to recount sin’s beginnings, he said sin passed on through a number that could not fit procreation, so that no one would think he had said anything to slander marriage instituted by God or blessed fertility. Certainly the first two human beings had both sinned, and both can rightly be called models of sin for their descendants. Why, then, did the apostle not say that sin passed on through two, which would have agreed better with the historical account? Nothing could have been wiser than his action. He saw that if he named the two who had provided the beginning and example of transgression, and affirmed that sin passed through them, there would be an opening for error: someone might think that by naming two he had condemned their union and fertility. Very wisely, therefore, he preferred to name one. Insufficient to indicate generation, one was more than enough to signify an example: accusing him would condemn imitation, while counting him would not accuse fertility. To sum up our argument briefly: the fertility instituted in the first human beings cannot operate except through two; but the apostle declares that sin entered through one.