… is from page 654 of Book IV, Chapter viii of the 1981 Liberty Fund edition of Adam Smith’s magisterial book – first published 241 years ago today, March 9th, 1776 – An Inquiry Into the Nature and Causes of the Wealth of Nations:
To hurt in any degree the interest of any one order of citizens, for no other purpose but to promote that of some other, is evidently contrary to that justice and equality of treatment which the sovereign owes to all the different orders of his subjects.