… is from page 62 of Jacob Viner‘s 1959 lecture “The Emergence of Free-Trade and Laissez-Faire Doctrine,” as this lecture is printed in the 1991 collection, edited by Douglas Irwin, Jacob Viner: Essays on the Intellectual History of Economics:
Beyond, moreover, its material benefits, it is clear that for Adam Smith laissez faire had ethical or moral value in that it left to the individual unimpaired “liberty” to which he had a natural right. It is quite probable, therefore, that Adam Smith would have rejected an extensive program of state regulation of economic enterprise even if he had believed that the wealth of nations could thereby be augmented.