No act without Christ's grace is truly good before God: 'splendid sins'
Thesis XI. The Protestants, however, hold with one accord that in this state of corrupted nature no moral good can be performed by man without the grace of Christ in such a way that the act is held truly good and just before God and is not to be counted among sins. So whatever men do without the grace of Christ, however much it has the look of virtue and some outward goodness and uprightness, does not escape the character of sin in God's judgement. Thus the finest and most glorious deeds of heroes are splendid sins, masks and likenesses of virtues, as Morus, often cited already, puts it with Augustine in thesis 42.
'By moral works,' he says, 'Bellarmine meant works that please God and such as God requires. In that sense we readily believe Augustine that man can do nothing at all, and that even his finest and most glorious deeds are splendid sins, masks and likenesses of virtues.' What we read in David Pareus agrees with this: 'We say that the moral virtues of the unregenerate, of whatever kind, done without faith and with an unclean heart, however upright, just and worthy of praise and reward they may be before the world, are nonetheless sins before God, not in their kind but by accident' (on Bellarmine, On grace and free choice, book 5, chapter 4).
He calls such virtues sins by accident because, though they are good things in their kind, they fall short in certain essentials. They do not arise from the proper principle, and they are not referred to the lawful end.
Latin
XI. Verum communi consensu statuunt Protestantes nullum bonum morale in hoc statu naturae corruptae, sine gratia Christi, ab homine sic perfici posse, ut actio coram Deo revera bona & justa habeatur, neque peccatis debeat accenseri. Ac proinde quaecunque ab hominibus sine Christi gratia fiunt, ut ut speciem virtutis habeant, & externam aliquam bonitatem atque honestatem, peccati rationem in judicio Dei non effugere; adeoque pulcherrima & illustrissima heroum facinora, splendida esse peccata, larvas & simulachra virtutum: ut cum Augustino loquitur saepe jam dictus Morus thesi 42. Bellarminus, inquit, per moralia opera, quae Deo jucunda sunt & qualia Deus postulat, intellexit: quo sensu plane nihil hominem posse, atque adeo pulcherrima ipsius & illustrissima facinora splendida, esse peccata, larvas & simulachra virtutum Augustino facile credimus. Quibus conforme est quod apud Davidem Paraeum legitur, Dicimus, inquit, morales non renatorum virtutes qualescunque, sine fide cum immunditia cordis factas, ut maxime coram mundo sint honestae, justae, laude & praemiis dignae: tamen coram Deo esse peccata, non quidem suo genere, sed per accidens. In lib. 5. Bellar. de gratia & libero Arbitrio, cap. 4. Dicit autem tales virtutes esse peccata per accidens, quoniam licet res sint ex suo genere bonae, in quibusdam tamen essentialibus deficiunt: nempe quia nec ex debito principio oriuntur, nec referuntur in legitimum finem.