Enchiridion of Epictetus Chapter 50

ὅσα προτίθεται, τούτοις ὡς νόμοις, ὡς ἀσεβήσων, ἂν παραβῇς, ἔμμενε. ὅ τι δʼ ἂν ἐρῇ τις περὶ σοῦ, μὴ ἐπιστρέφου· τοῦτο γὰρ οὐκ ἔτʼ ἔστι σόν.

Whatever things (rules) are proposed to you (for the conduct of life) abide by them, as if they were laws, as if you would be guilty of impiety if you transgressed any of them. And whatever any man shall say about you, do not attend to it; for this is no affair of yours.

À tous ces préceptes, comme à des lois que tu ne peux sans impiété transgresser, reste fidèle. De tout ce qu’on pourra dire de toi, ne prends souci : cela n’est plus ton fait.