Moralis non potest esse passio, quia passio est motus quidam appetitus sensitivi, ut supra dictum est. Virtus autem moralis non est motus aliquis, sed magis principium appetitivi motus, habitus quidam existens.
Moral virtue cannot be a passion because a passion is a movement of the sensitive appetite, as stated above (q22 a3), whereas moral virtue is not a movement, but rather a principle of the movement of the appetite, being a kind of habit.
Passiones ex seipsis non habent rationem boni vel mali. Bonum enim vel malum hominis est secundum rationem: unde passiones, secundum se consideratae, se habent et ad bonum et ad malum, secundum quod possunt convenire rationi vel non convenire. Nihil autem tale potest esse virtus, cum virtus solum ad bonum se habeat, ut supra dictum est.
Passions do not in themselves have the formal aspect of good or evil. For man's good or evil is something in reference to formal aspect: wherefore the passions, considered in themselves, are referable both to good and evil, for as much as they may accord or disaccord with formal aspect. Now nothing of this sort can be a virtue, since virtue is referable to good alone, as stated above (q55 a3).
Dato quod aliqua passio se habeat solum ad bonum, vel solum ad malum, secundum aliquem modum, tamen motus passionis, inquantum passio est, principium habet in ipso appetitu, et terminum in ratione, in cuius conformitatem appetitus tendit. Motus autem virtutis est e converso, principium habens in ratione et terminum in appetitu, secundum quod a ratione movetur.
Granted that some passions are, in some way, referable to good only, or to evil only, even then the movement of passion, as passion, begins in the appetite, and ends in the reason, since the appetite tends to conformity with reason. On the other hand, the movement of virtue is the reverse, for it begins in the reason and ends in the appetite, inasmuch as the latter is moved by reason.
Unde in definitione virtutis moralis dicitur, in II Ethic., quod est "habitus electivus in medietate consistens determinata ratione, prout sapiens determinabit".
Hence the definition of moral virtue (Ethic. ii, 6) states that it is "a habit of choosing the mean determined by reason, as a prudent man would determine it".
Dicitur in II Ethic., quod "passiones neque virtutes sunt neque malitiae".
It is stated in Ethic. ii, 5 that "passions are neither virtues nor vices".