The Wealth of Nations by Part 4 Chapter 3 Page 64

rapacity, the monopolizing spirit of merchants and manufacturers, who neither are, nor ought to be, the rulers of mankind, though it cannot perhaps be corrected may very easily be prevented from disturbing the tranquillity of anybody but themselves.

That it was the spirit of monopoly which originally both invented and propagated this doctrine cannot be doubted; and they who first taught it were by no means such fools as they who believed it. In every country it always is and must be the interest of the great body of the people to buy whatever they want of those who sell it cheapest. The proposition is so very manifest that it seems ridiculous to take any pains to prove it; nor could it ever have been called in question had not the interested sophistry of merchants and manufacturers confounded the common sense of mankind.