On the contrary, It is written (Luke 7:43): "To whom more is forgiven, he loveth more [*Vulg.: 'To whom less is forgiven, he loveth less' Luke 7:47]." Therefore for the same reason he is bound to greater thanksgiving.
I answer that, Thanksgiving (gratiarum actio) in the recipient corresponds to the favor (gratia) of the giver: so that when there is greater favor on the part of the giver, greater thanks are due on the part of the recipient. Now a favor is something bestowed gratis: wherefore on the part of the giver the favor may be greater on two counts. First, owing to the quantity of the thing given: and in this way the innocent owes greater thanksgiving, because he receives a greater gift from God, also, absolutely speaking, a more continuous gift, other things being equal. Secondly, a favor may be said to be greater, because it is given more gratuitously; and in this sense the penitent is more bound to give thanks than the innocent, because what he receives from God is more gratuitously given: since, whereas he was deserving of punishment, he has received grace. Wherefore, although the gift bestowed on the innocent is, considered absolutely, greater, yet the gift bestowed on the penitent is greater in relation to him: even as a small gift bestowed on a poor man is greater to him than a great gift is to a rich man. And since actions are about singulars, in matters of action, we have to take note of what is such here and now, rather than of what is such absolutely, as the Philosopher observes (Ethic. iii) in treating of the voluntary and the involuntary.
This suffices for the Replies to the Objections. _______________________
THIRD ARTICLE [II-II, Q. 106, Art. 3]
Whether a Man Is Bound to Give Thanks to Every Benefactor?
Objection 1: It seems that a man is not bound to give thanks to every benefactor. For a man may benefit himself just as he may harm himself, according to Ecclus. 14:5, "He that is evil to himself, to whom will he be good?" But a man cannot thank himself, since thanksgiving seems to pass from one person to another. Therefore thanksgiving is not due to every benefactor.
Obj. 2: Further, gratitude is a repayment of an act of grace. But some favors are granted without grace, and are rudely, slowly and grudgingly given. Therefore gratitude is not always due to a benefactor.
Obj. 3: Further, no thanks are due to one who works for his own profit. But sometimes people bestow favors for their own profit. Therefore thanks are not due to them.
Obj. 4: Further, no thanks are due to a slave, for all that he is belongs to his master. Yet sometimes a slave does a good turn to his master. Therefore gratitude is not due to every benefactor.
Obj. 5: Further, no one is bound to do what he cannot do equitably and advantageously. Now it happens at times that the benefactor is very well off, and it would be of no advantage to him to be repaid for a favor he has bestowed. Again it happens sometimes that the benefactor from being virtuous has become wicked, so that it would not seem equitable to repay him. Also the recipient of a favor may be a poor man, and is quite unable to repay. Therefore seemingly a man is not always bound to repayment for favors received.