『쾌락과 절제， 친구의 가치와 소중함에 대한 소크라테스의 담론』 ２부

There is nothing truly valuable which can be purchased without pains and labor. The gods have set a price upon every real and noble pleasure. If you would gain the favor of the Deity, you must be at the pains of worshipping Him; if you would be beloved by your friends, you must study to oblige them. If you would be honored by any city, you must be of service to it. Each man should consider how much he can be worth to his friends, and should endeavor to render himself as valuable as he can in their regard.