To Florus 1.108

He immediately adds that they are slaves of righteousness in the same way that they had previously been slaves of sin. You may now, if you wish, call them free from sin when they serve righteousness, just as he called them free from righteousness when they served wrongdoing. Most foolishly, then, you wanted to bring an accusation against the apostle's straightforward language. He did not, as you think, very carefully indicate the point you imagine; rather, you are very sleepily examining what he said. You argue that he preferred to say “freed” rather than “free” so that we would understand that freedom of choice enables evil but cannot bring about good. Yet the very order of his words resists you. If he had thought as you do, that freedom produced only sin, he should have said, “You were free for sin”, not “You were free for righteousness” (Romans 6:20), so that a person would be called free with respect to what that freedom accomplished. If we are to weigh even the force of grammatical cases, he said that they were free “for this righteousness”, not free “from this righteousness”. His phrasing would therefore help us more consistently, if we too wished to press such slight matters. Far be it from us! We understand the apostle's meaning and are content with the service of words straightforwardly spoken.

The Teacher of the Nations meant nothing other than: “You were free; you did not serve righteousness. You have been freed; you have received forgiveness of sins.” Freedom of choice remains, through which they could obey sin before and righteousness afterward.