Epictetus, Works, book 4, Πρὸσ τοὺσ ἐπὶ τῷ ἐλεεῖσθαι ὀδυνωμένουσ. 9:

πρὸσ ταῦτα οὖν οὐκ ἀκήκοασ, ὅτι μία ἐστὶν ἡ ὁδὸσ ἡ φέρουσα, ἀφεῖναι τὰ ἀπροαίρετα καὶ ἐκστῆναι αὐτῶν καὶ ὁμολογῆσαι αὐτὰ ἀλλότρια;