I answer that, As stated above (I-II, Q. 60, A. 3), the nature of the debt to be paid must needs vary according to various causes giving rise to the debt, yet so that the greater always includes the lesser. Now the cause of debt is found primarily and chiefly in God, in that He is the first principle of all our goods: secondarily it is found in our father, because he is the proximate principle of our begetting and upbringing: thirdly it is found in the person that excels in dignity, from whom general favors proceed; fourthly it is found in a benefactor, from whom we have received particular and private favors, on account of which we are under particular obligation to him.
Accordingly, since what we owe God, or our father, or a person excelling in dignity, is not the same as what we owe a benefactor from whom we have received some particular favor, it follows that after religion, whereby we pay God due worship, and piety, whereby we worship our parents, and observance, whereby we worship persons excelling in dignity, there is thankfulness or gratitude, whereby we give thanks to our benefactors. And it is distinct from the foregoing virtues, just as each of these is distinct from the one that precedes, as falling short thereof.
Reply Obj. 1: Just as religion is superexcelling piety, so is it excelling thankfulness or gratitude: wherefore giving thanks to God was reckoned above (Q. 83, A. 17) among things pertaining to religion.
Reply Obj. 2: Proportionate repayment belongs to commutative justice, when it answers to the legal due; for instance when it is contracted that so much be paid for so much. But the repayment that belongs to the virtue of thankfulness or gratitude answers to the moral debt, and is paid spontaneously. Hence thanksgiving is less thankful when compelled, as Seneca observes (De Beneficiis iii).
Reply Obj. 3: Since true friendship is based on virtue, whatever there is contrary to virtue in a friend is an obstacle to friendship, and whatever in him is virtuous is an incentive to friendship. In this way friendship is preserved by repayment of favors, although repayment of favors belongs specially to the virtue of gratitude. _______________________
SECOND ARTICLE [II-II, Q. 106, Art. 2]
Whether the Innocent Is More Bound to Give Thanks to God Than the
Penitent?
Objection 1: It seems that the innocent is more bound to give thanks to God than the penitent. For the greater the gift one has received from God, the more one is bound to give Him thanks. Now the gift of innocence is greater than that of justice restored. Therefore it seems that the innocent is more bound to give thanks to God than the penitent.
Obj. 2: Further, a man owes love to his benefactor just as he owes him gratitude. Now Augustine says (Confess. ii): "What man, weighing his own infirmity, would dare to ascribe his purity and innocence to his own strength; that so he should love Thee the less, as if he had less needed Thy mercy, whereby Thou remittest sins to those that turn to Thee?" And farther on he says: "And for this let him love Thee as much, yea and more, since by Whom he sees me to have been recovered from such deep torpor of sin, by Him he sees himself to have been from the like torpor of sin preserved." Therefore the innocent is also more bound to give thanks than the penitent.
Obj. 3: Further, the more a gratuitous favor is continuous, the greater the thanksgiving due for it. Now the favor of divine grace is more continuous in the innocent than in the penitent. For Augustine says (Confess. iii): "To Thy grace I ascribe it, and to Thy mercy, that Thou hast melted away my sins as it were ice. To Thy grace I ascribe also whatsoever I have not done of evil; for what might I not have done? . . . Yea, all I confess to have been forgiven me, both what evils I committed by my own wilfulness, and what by Thy guidance committed not." Therefore the innocent is more bound to give thanks than the penitent.