Enchiridion · §30

τὰ καθήκοντα ὡς ἐπίπαν ταῖς σχέσεσιν παραμετρεῖται. πατήρ ἐστιν; ὑπακούειν, παραχωρεῖν ἐν πᾶσιν, ἀνέχεσθαι λοιδοροῦντος, παίοντος. "ἀλλὰ πατὴρ κακός ἐστιν." μή τι οὖν πρὸς ἀγαθὸν πατέρα φύσει ᾠκειώθης; ἀλλὰ πρὸς πατέρα."ὁ ἀδελφός μου ἀδικεῖ." τήρει τοιγαροῦν τὴν τάξιν τὴν σεαυτοῦ πρὸς αὐτόν, μηδ᾽ ἐπισκόπει τί ἐκεῖνος ποιεῖ, ἀλλὰ τί σοὶ ποιοῦντι κατὰ φύσιν ἕξει ἡ σὴ προαίρεσις.

ta kathēkonta hōs epipan tais schesesin parametreitai. patēr estin? hupakouein, parachōrein en pasin, anechesthai loidorountos, paiontos. 'alla patēr kakos estin.' mē ti oun pros agathon patera phusei ōikeiōthēs? alla pros patera. 'ho adelphos mou adikei.' tērei toigaroun tēn taxin tēn seautou pros auton.

Our duties are generally defined by our relationships. When someone is your father, the duty is to care for him, defer to him, and endure his harshness — even when he is a bad father. Your natural tie is to fatherhood, not to a good father. When your brother wrongs you, hold to your proper role toward him and do not occupy yourself with what he is doing wrong; concern yourself only with what your own prohairesis requires of you.

— Enchiridion 30

Source: Greek (Schenkl/Oldfather critical edition tradition) + Long 1877 English translation