Adam Smith Quote
Every individual necessarily labours to render the annual revenue of society as great as he can. He generally neither intends to promote the public interest, nor knows how much he is promoting it. He intends only his own gain, and he is, in this, as in many other cases, led by an invisible hand to promote an end which was no part of his intention.
Wealth of Nations (1776) bk. 4, ch. 3