We can’t be happy, but we can be good; let us therefore pretend that, so long as we are good, it doesn’t matter being unhappy.
 Bertrand Russell, A History of Western Philosophy (1945). copy citation

Context

“This doctrine involves no logical contradiction, but it loses all plausibility if we genuinely believe that what are commonly considered goods are worthless, for in that case the virtuous will might just as well be directed to quite other ends. There is, in fact, an element of sour grapes in Stoicism. We can’t be happy, but we can be good; let us therefore pretend that, so long as we are good, it doesn’t matter being unhappy. This doctrine is heroic, and, in a bad world, useful; but it is neither quite true nor, in a fundamental sense, quite sincere. Although the main importance of the Stoics was ethical, there were two respects in which their teaching bore fruit in other fields.” source