… is from is from Book IV, Chapter 8 – on page 660, Vol. 2, of the 1981 Liberty Fund edition – of Adam Smith’s 1776 An Inquiry Into the Nature and Causes of the Wealth of Nations:
Consumption is the sole end and purpose of all production; and the interest of the producer ought to be attended to only so far as it may be necessary for promoting that of the consumer. The maxim is so perfectly self-evident that it would be absurd to attempt to prove it. But in the mercantile system the interest of the consumer is almost constantly sacrificed to that of the producer; and it seems to consider production, and not consumption, as the ultimate end and object of all industry and commerce.