… is from page 163 of volume III (“The Political Order of a Free People,” 1979) of Hayek’s Law, Legislation, and Liberty  (original emphasis):
Man has not developed in freedom. The member of the little band to which he had to stick in order to survive was anything but free. Freedom is an artifact of civilization that released man from the trammels of the small group, the momentary moods of which even the leader had to obey. Freedom was made possible by the gradual evolution of the discipline of civilization which is at the same time the discipline of freedom.