[22] [cap.4] Then, after these contests in which repentance is concerned, he proposes a third class of prizes, relating to justice, which every one who practises obtains a twofold reward; in the first place, that of preservation at the time of general destruction; and secondly, that of being the steward and guardian of every description of animal which is coupled in pairs for the purpose of raising a second stock instead of that which from time to time perishes;