Eudokimoiēs

Μηδέποτε μηδὲν αἰσχρὸν ποιήσας ἔλπιζε λήσειν· καὶ γὰρ ἂν τοὺς ἄλλους λάθῃς, σεαυτῷ συνειδήσεις.
τοὺς μὲν θεοὺς φοβοῦ, τοὺς δὲ γονεῖς τίμα, τοὺς δὲ φίλους αἰσχύνου, τοῖς δὲ νόμοις πείθου.
τὰς ἡδονὰς θήρευε τὰς μετὰ δόξης· τέρψις γὰρ σὺν τῷ καλῷ μὲν ἄριστον, ἄνευ δὲ τούτου κάκιστον.
εὐλαβοῦ τὰς διαβολάς, κἂν ψευδεῖς ὦσιν· οἱ γὰρ πολλοὶ τὴν μὲν ἀλήθειαν ἀγνοοῦσι, πρὸς δὲ τὴν δόξαν ἀποβλέπουσιν. ἅπαντα δόκει ποιεῖν ὡς μηδένα λήσων· καὶ γὰρ ἂν παραυτίκα κρύψῃς, ὕστερον ὀφθήσει. μάλιστα δ᾽ ἂν εὐδοκιμοίης, εἰ φαίνοιο ταῦτα μὴ πράττων, ἃ τοῖς ἄλλοις ἂν πράττουσιν ἐπιτιμῴης.
(Isocrates, Or. 1.16-17)

Never hope to conceal any shameful thing which you have done; for even if you do conceal it from others, your own heart will know.
Fear the gods, honor your parents, respect your friends, obey the laws.
Pursue the enjoyments which are of good repute; for pleasure attended by honor is the best thing in the world, but pleasure without honor is the worst.
Guard yourself against accusations, even if they are false; for the multitude are ignorant of the truth and look only to reputation. In all things resolve to act as though the whole world would see what you do; for even if you conceal your deeds for the moment, later you will be found out. But most of all will you have the respect of men, if you are seen to avoid doing things which you would blame others for doing. (tr. George Norlin)