Plutarch, De Tranquilitate Animi 467b
“Plato likened life to a dice-game in which we need both to throw what is advantageous and to use the dice well after we’ve thrown them. And when we are subject to chance, if we take good advice, this is our task: though we cannot control the toss, we can accept the outcome luck gives us properly and allot to each event a place in which what is good for us helps the most and what was unplanned aggrieves the least.”
Κυβείᾳ γὰρ ὁ Πλάτων (Resp. 604c) τὸν βίον ἀπείκασεν, ἐν ᾧ καὶ βάλλειν δεῖ τὰ πρόσφορα, καὶ βαλόντα χρῆσθαι καλῶς τοῖς πεσοῦσι. τούτων δὲ τὸ μὲν βάλλειν οὐκ ἐφ’ ἡμῖν, τὸ δὲ προσηκόντως δέχεσθαι τὰ γινόμενα παρὰ τῆς τύχης καὶ νέμειν ἑκάστῳ τόπον, ἐν ᾧ καὶ τὸ οἰκεῖον ὠφελήσει μάλιστα καὶ τὸ ἀβούλητον ἥκιστα λυπήσει τοὺς ἐπιτυγχάνοντας, ἡμέτερον ἔργον ἐστίν, ἂν εὖ φρονῶμεν.
And here is the passage Plutarch is drawing on from the tenth book of the Republic (Plato, Republic 604c-d)
“The best way to deliberate about what has happened is just as we might in the fall of dice: to order our affairs in reference to how the dice have fallen where reason dictates the best place would be, and not to stumble forward like children shocked at the outcome wasting time with crying. Instead, we should always prepare our mind towards addressing what has happened as quickly as possible and to redress what has fallen and what ails, erasing lament [lit. threnody] with treatment*.”
Τῷ βουλεύεσθαι, ἦν δ’ ἐγώ, περὶ τὸ γεγονὸς καὶ ὥσπερ ἐν πτώσει κύβων πρὸς τὰ πεπτωκότα τίθεσθαι τὰ αὑτοῦ πράγματα, ὅπῃ ὁ λόγος αἱρεῖ βέλτιστ’ ἂν ἔχειν, ἀλλὰ μὴ προσπταίσαντας καθάπερ παῖδας ἐχομένους τοῦ πληγέντος ἐν τῷ βοᾶν διατρίβειν, ἀλλ’ ἀεὶ ἐθίζειν τὴν ψυχὴν ὅτι τάχιστα γίγνεσθαι πρὸς τὸ ἰᾶσθαί τε καὶ ἐπανορθοῦν τὸ πεσόν τε καὶ νοσῆσαν, ἰατρικῇ θρηνῳδίαν ἀφανίζοντα.
*ἰατρικῇ: lit. “art of medicine”; some translations use “therapy”.