Passage 4.22.3
Ἀριστομένει δὲ ὅ τε οἶκτος διαρπαζομένης τῆς Εἴρας καὶ τὸ μῖσος τὸ ἐς τοὺς Λακεδαιμονίους βούλευμα παρίστησι τοιόνδε. πεντακοσίους τῶν Μεσσηνίων, οὓς μάλιστα ἠπίστατο αὑτῶν ἀφειδῶς ἔχοντας, ἀποκρίνας ἀπὸ τοῦ πλήθους, ἤρετο σφᾶς ἐν ἐπηκόῳ τῶν τε ἄλλων Ἀρκάδων καὶ Ἀριστοκράτους, ἅτε ὄντα προδότην οὐκ εἰδώς---ἀνανδρίᾳ γὰρ καὶ ὑπὸ δειλίας φυγεῖν τότε ἤδη Ἀριστοκράτην τῆς μάχης καὶ οὐ διὰ κακίαν οὐδεμίαν ἐδόξαζεν αὐτόν, ὥστε ἐναντίον καὶ τούτου τοὺς πεντακοσίους ἤρετο---, εἰ τιμωροῦντες τῇ πατρίδι ἀποθνήσκειν σὺν αὑτῷ ἐθελήσουσι.
Pity for the sacking of Eira and hatred against the Lacedaemonians prompted Aristomenes to devise the following plan. Selecting from the entire body of Messenians five hundred whom he knew to be especially heedless of their own lives, Aristomenes asked them in the hearing of the Arcadians and of Aristocrates, whom he did not yet recognize as a traitor—for he supposed that Aristocrates had abandoned the battle merely from cowardice and fear, not suspecting any deeper wickedness, and thus posed the question openly before his eyes to the five hundred—whether they were willing to die with him in vengeance for their country.