… is from pages 120-121 of F.A. Hayek’s 1950 paper “The Meaning of Government Interference,” which appears for the first time in print as Chapter 8 of Essays on Liberalism and the Economy (2022), which is volume 18 (expertly edited by Paul Lewis) of The Collected Works of F.A. Hayek:
Unless we are willing to restrict the powers of government even in respects where it might be used for good purposes, we shall not succeed in preventing an indefinite growth of government powers. To allow everything which seems expedient for the achievement of a desirable end is to dispense with all moral principles. The submission to rules which must be observed irrespective of whether in the particular instance their infringement is harmful or not, is the main condition for the possibility of order in a free society. And to these rules the state should be no less subject than the individual.