" Consider what intemperate lovers undergo for the sake of evil desires, and how much exertion others expend for the sake of making profit, and how much suffering those who are pursuing fame endure, and bear in mind that all of these people submit to all kinds of toil and hardship voluntarily. Is it then not monstrous that they for no honorable reward endure such things, while we for the sake of the ideal good - that is not only the avoidance of evil such as wrecks our lives, but also the acquisition of virtue, which we may call the provider of all goods -- are not ready to bear every hardship?
And yet would not anyone admit how much better it is, in place of exerting oneself to win someone else's wife, to exert oneself the discipline of one's desires; in place of enduring hardships for the sake of money, the train oneself to want little; instead of giving oneself trouble about getting notoriety; instead of trying to find a way to injure an envied person, to enquire how not to envy anyone; and instead of slaving, as sycophants do, to win false friends, to undergo suffering in order to possess true friends?
Since toil and hardship are a necessity for all, both for those who seek better and worse, it is preposterous that those pursuing the better are not much more eager in their efforts than those for whom there is small hope of reward for all their pains. ...
It remains for me to say that who is unwilling to exert himself almost always convicts himself as unworthy of good, since all good is gained by toil. "

― , Musonius Rufus: Lectures and Sayings