Meditations 5.22.1
Marcus Aurelius to himself
Ὃ τῇ πόλει οὐκ ἔστι βλαβερόν, οὐδὲ τὸν πολίτην βλάπτει. ἐπὶ πάσης τῆς τοῦ βεβλάφθαι φαντασίας τοῦτον ἔπαγε τὸν κανόνα· εἰ ἡ πόλις ὑπὸ τούτου μὴ βλάπτεται, οὐδὲ ἐγὼ βέβλαμμαι· εἰ δὲ ἡ πόλις βλάπτεται, οὐκ ὀργιστέον, ἀλλὰ δεικτέον τῷ βλάπτοντι τὴν πόλιν τί τὸ παρορώμενον.
What does not harm the city does not harm the citizen either. Apply this rule to every impression that you have been harmed: if the city is not harmed by this, neither have I been harmed. But if the city is harmed, you must not be angry; you must show the person harming the city what he is overlooking.