Letters from a Stoic 16 : 2

Hence you no longer need to come to me with much talk and protestations; I know that you have made great progress. I understand the feelings which prompt your words; they are not feigned or specious words. Nevertheless I shall tell you what I think, – that at present I have hopes for you, but not yet perfect trust. And I wish that you would adopt the same attitude towards yourself; there is no reason why you should put confidence in yourself too quickly and readily. Examine yourself; scrutinize and observe yourself in divers ways; but mark, before all else, whether it is in philosophy or merely in life itself that you have made progress.