"The conception of duty, speaking historically, has been a means used by the holders of power to induce others to live for the interests of their masters rather than for their own. Of course the holders of power conceal this fact from themselves by managing to believe that their interests are identical with the larger interests of humanity. Sometimes this is true; Athenian slave-owners, for instance, employed part of their leisure in making a permanent contribution to civilization which would have been impossible under a just economic system. Leisure is essential to civilization, and in former times leisure for the few was only rendered possible by the labors of the many. But their labors were valuable, not because work is good, but because leisure is good. And with modern technique it would be possible to distribute leisure justly without injury to civilization."
January 1, 1970
https://en.wikiquote.org/wiki/Power