Whether grace is the principle of merit through charity rather than the other virtues?

❌ Objection 1 : It would seem that grace is not the principle of merit through charity rather than the other virtues. For wages are due to work, according to Mt. 20:8: "Call the laborers and pay them their hire." Now every virtue is a principle of some operation, since virtue is an operative habit, as stated above (Question [55], Article [2]). Hence every virtue is equally a principle of merit.

❌ Objection 2 : Further, the Apostle says (1 Cor. 3:8): "Every man shall receive his own reward according to his labor." Now charity lessens rather than increases the labor, because as Augustine says (De Verbis Dom., Serm. lxx), "love makes all hard and repulsive tasks easy and next to nothing." Hence charity is no greater principle of merit than any other virtue.

❌ Objection 3 : Further, the greatest principle of merit would seem to be the one whose acts are most meritorious. But the acts of faith and patience or fortitude would seem to be the most meritorious, as appears in the martyrs, who strove for the faith patiently and bravely even till death. Hence other virtues are a greater principle of merit than charity.