Do not because a thing is hard for you yourself to accomplish, imagine that it is humanly impossible: but if a thing is humanly possible and appropriate, consider it also to be within your own reach.[Μή, εἴ τι αὐτῷ σοὶ δυσκαταπόνητον, τοῦτο ἀνθρώπῳ ἀδύνατον ὑπολαμβάνειν, ἀλλ εἴ τι ἀνθρώπῳ δυνατὸν καὶ οἰκεῖον, τοῦτο καὶ σεαυτῷ ἐφικτὸν νομίζειν.]

Source:The Meditations of Marcus Aurelius Antoninus (ed. Oxford, 1990), (tr. Farquharson), Book 6, #19, Page 47
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