But man has almost constant occasion for the help of his brethren, and it is in vain for him to expect it from their benevolence only. … It is not from the benevolence of the butcher, the brewer, or the baker, that we expect our dinner, but from their regard to their own interest. We address ourselves, not to their humanity but to their self-love, and never talk to them of our own necessities but of their advantages.

Adam Smith (1776). The Wealth of Nations, p 26-27