From Margaret R. Graver's Stoicism and Emotion:
"Now the chief insight of Stoic axiology could very well be expressed this way: that in a rational being, external objects never merit uncompromising evaluation but integral objects always do . . . They speak most often of integral objects in terms of 'virtue' and 'vice' and of uncompromising evaluation in terms of what is seen as genuinely good or evil. So the claim often appears in the form 'virtue is the only good, vice the only evil.' More precise treatments make it clear that the class of genuine goods and evils includes not only characteristics of persons but also any impulse that counts as an exercise of virtue or vice."
What Graver refers to as "external objects" are, in more traditional Stoic terminology, "indifferents." "To call such objects 'indifferents' is not to say that one has to be indifferent to them; indeed, one might pursue them strenuously on the basis of a restricted evaluation, in what the Stoics call 'selection' or 'disselection.' But these are objects which do not in themselves make life different, turning a good life into a bad life or vice versa. What matters about them is only how they are used, the adverbial aspect, as it were, of our engagement with them. Virtues and faults must have something to work with if they are to be exercised. Fighting courageously in battle requires a battle to fight in . . . acquiring money honestly means there was money to acquire. But in each case the elements of those activities that are external to the agent's control are not integral to the evaluation. If we think the fighting or the acquisition is good in itself, we are making a mistake."