… is from page 9 of Frank Knight’s 1956 collection, On the History and Method of Economics; specifically, it’s from Knight’s 1951 Encyclopaedia Britannica essay titled “Economics”:
Although the book [Adam Smith’s An Inquiry Into the Nature and Causes of the Wealth of Nations] is the most influential brief ever formulated for unimpeded trade, neither hampered nor coddled by governments, its greatest importance lies not in that circumstance but in the general picture, at once simple and comprehensive, which it gives of the economic life of a nation. The apparent chaos of competition, the welter of buying and selling, are resolved or transmuted into an orderly system of economic co-operation by means of which, under individual freedom in contrast with central direction, the community’s wants are supplied and its wealth increased.