The Theory of Moral Sentiments by Adam Smith

1. We do not therefore thoroughly and heartily sympathize with the gratitude of one man towards another, merely because this other has been the cause of his good fortune, unless he has been the cause of it from motives which we entirely go along with. Our heart must adopt the principles of the agent, and go along with all the affections which influenced his conduct, before it can entirely sympathize with and beat time to, the gratitude of the person who has been benefited by his actions. If in the conduct of the benefactor there appears to have been no propriety, how beneficial soever its effects, it does not seem to demand, or necessarily to require, any proportionable recompense.

But when to the beneficent tendency of the action is joined the propriety of the affection from which it proceeds, when we entirely sympathize and go along with the motives of the agent, the love which we conceive for him upon his own account enhances and enlivens our fellow-feeling with the gratitude of those who owe their prosperity to his good conduct. His actions seem then to demand, and, if I may say so, to call aloud for a proportionable recompense. We then entirely enter into that gratitude which prompts to bestow it. The benefactor seems then to be the proper object of reward, when we thus entirely sympathize with, and approve of, that sentiment which prompts to reward him. When we approve of, and go along with, the affection from which the action proceeds, we must necessarily approve of the action, and regard the person towards whom it is directed, as its proper and suitable object.