Protagoras did not know if the gods exist, but he held in any case they ought to be worshiped. Philosophy, according to him, had nothing edifying to teach, and for the survival of morals we must rely upon the thoughtlessness of the majority and their willingness to believe what they had been taught.
Bertrand Russell, Robert Edward Egner (1961). “The basic writings of Bertrand Russell, 1903-1959”