Robert Bellarmine (1542-1621): If, however, the Pope should err by enjoining vices and forbidding virtues, that is, he will enjoin a particular work, although it would be actually vice, but not obvious vice, or prohibit a good work but not an obvious good work, the Church would be bound to believe vices to be good, and virtues to be evil, unless she would be willing to sin against conscience.
Latin text: Si autem Papa erraret praecipiendo vitia, vel prohibendo virtutes, id est, praecipiendo aliquod opus, quod esset revera vitiosum, sed non manifeste vitiosum, vel prohibendo opus virtutis, sed non manifeste opus virtutis teneretur Ecclesia credere vitia esse bona, et virtutes malas, nisi vellet conscientiam peccare. Roberti Bellarmini, De Controversiis, Tomus Primus, De Romano Pontifice (Neapoli: Apud Josephum Giuliano, 1856), Liber Quartus, Caput 5, p. 495.