To Florus 2.229

The apostle, however—if he can obtain any credibility from people in this age—shows that he calls none slaves of sin except those who are known to have obeyed sin by their own will. By changing that will, they began to serve righteousness. He therefore placed obedience in the middle and attributed to it their effort to obey vices earlier and virtues afterward (compare Romans 6:16–18).