Plato, Letters 315b

τυγχάνοιμι τῆς βελτίστης προσρήσεως; ἢ μᾶλλον κατὰ τὴν ἐμὴν συνήθειαν γράφων εὖ πράττειν, ὥσπερ εἴωθα ἐν ταῖς ἐπιστολαῖς τοὺς φίλους προσαγορεύειν; σὺ μὲν γὰρ δὴ καὶ τὸν θεόν, ὡς ἤγγειλαν οἱ τότε θεωροῦντες, προσεῖπες ἐν Δελφοῖς αὐτῷ τούτῳ θωπεύσας τῷ ῥήματι, καὶ γέγραφας, ὡς φασί, χαῖρε καὶ ἡδόμενον βίοτον διάσῳζε τυράννου·

should I be hitting on the best mode of address? Or rather, by writing, according to my custom, Wishes well-doing, this being my usual mode of address, in my letters to my friends? You, indeed,—as was reported by the spectators then present—addressed even the God himself at Delphi in this same flattering phrase, and wrote, as they say, this verse—I wish you joy! And may you always keep The tyrant’s life a life of pleasantness.