To Florus 2.107

What, then, has this argument established? That your understanding does not agree with the apostle. The apostle says that many offenses are forgiven by grace’s generosity. Your doctrine, however, asserts that one natural sin, which you call the law of sin, fashions desires for wickedness in all human beings. Plainly, then, you accuse nature, which is God’s work, while he accuses the will. He ought not to have spoken otherwise than he did: condemnation can result from one sin. For that first man supplied an example of wrongdoing through one sin, and just as one transgression was enough to condemn him, so one fault can suffice to make others guilty. Hence Ecclesiastes says, ‘Whoever sins in one thing destroys much good’ (Ecclesiastes 9:18); and James: ‘If you keep the whole law but stumble in one point, you have become guilty of all’ (James 2:10).