Labor was the first price, the original purchase-money that was paid for all things. It was not by gold or by silver, but by labor, that all wealth of the world was originally purchased. – Adam Smith
The propensity to truck, barter and exchange one thing for another is common to all men, and to be found in no other race of animals. – Adam Smith
The real and effectual discipline which is exercised over a workman is that of his customers. It is the fear of losing their employment which restrains his frauds and corrects his negligence. – Adam Smith
Little else is requisite to carry a state to the highest degree of opulence from the lowest barbarism but peace, easy taxes, and a tolerable administration of justice: all the rest being brought about by the natural course of things. – Adam Smith