Moralists will never succeed in making us comprehend the full extent of the influence of sentiment upon self-interest, an influence every whit as strong as the action of interest upon our sentiments
 Honoré de Balzac, Lost Illusions (1843). copy citation

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Author Honoré de Balzac
Source Lost Illusions
Topic action interest
Date 1843
Language English
Reference
Note Translated by Ellen Marriage
Weblink https://www.gutenberg.org/cache/epub/13159/pg13159.html

Context

“He was mentally incapable of understanding his son; he laid the blame of failure upon him, and even prided himself, as it were on his superiority to a far greater intellect than his own, with the thought, "I am securing his bread for him." Moralists will never succeed in making us comprehend the full extent of the influence of sentiment upon self-interest, an influence every whit as strong as the action of interest upon our sentiments; for every law of our nature works in two ways, and acts and reacts upon us. David, on his side, understood his father, and in his sublime charity forgave him. Kolb and David reached Marsac at eight o'clock, and suddenly came in upon the old man as he was finishing his dinner, which, by force of circumstances, came very near bedtime.” source