Ingratitude is not to be found in the heart of man, but self-interest is there; those who are ungrateful for benefits received are fewer than those who do a kindness for their own ends.
 Jean-Jacques Rousseau, Emile, or On Education (1762). copy citation

add
Author Jean-Jacques Rousseau
Source Emile, or On Education
Topic kindness ingratitude
Date 1762
Language English
Reference
Note Translated by Barbara Foxley
Weblink http://www.gutenberg.org/cache/epub/5427/pg5427-images.html

Context

“is it not still more unjust to demand from your pupil the price of care which he has not even accepted! Ingratitude would be rarer if kindness were less often the investment of a usurer. We love those who have done us a kindness; what a natural feeling! Ingratitude is not to be found in the heart of man, but self-interest is there; those who are ungrateful for benefits received are fewer than those who do a kindness for their own ends. If you sell me your gifts, I will haggle over the price; but if you pretend to give, in order to sell later on at your own price, you are guilty of fraud; it is the free gift which is beyond price. The heart is a law to itself;” source