Οἱ δ’ Ἀθηναῖοι τὴν αὔξησιν ὑφορώμενοι τοῦ Φιλίππου τοῖς ἀεὶ πολεμουμένοις ὑπὸ τοῦ βασιλέως ἐβοήθουν, πρέσβεις ἀποστέλλοντες ἐπὶ τὰς πόλεις καὶ παρακαλοῦντες τηρεῖν τὴν αὐτονομίαν καὶ τοὺς ἐπὶ τὴν προδοσίαν ὁρμῶντας τῶν πολιτῶν θανάτῳ κολάζειν· ἐπηγγέλλοντο δὲ πᾶσι συμμαχήσειν καὶ φανερῶς ἑαυτοὺς πολεμίους ἀποδείξαντες τῷ βασιλεῖ διεπολέμουν πρὸς Φίλιππον. μάλιστα δ᾽ αὐτοὺς παρώξυνε προστῆναι τῆς Ἑλλάδος Δημοσθένης ὁ ῥήτωρ, δεινότατος ὢν τῶν κατ᾽ ἐκείνους τοὺς χρόνους Ἑλλήνων. οὐ μὴν ἡ πόλις γε ἀναστεῖλαι τῆς ἐπὶ τὴν προδοσίαν ὁρμῆς ἠδυνήθη τοὺς πολίτας· τοιαύτη γὰρ φορά τις προδοτῶν ὑπῆρξε τότε κατὰ τὴν Ἑλλάδα. διὸ καί φασι τὸν Φίλιππον βουλόμενον ἑλεῖν τινα πόλιν ὀχυρότητι διαφέρουσαν, εἰπόντος τινὸς αὐτῷ τῶν ἐγχωρίων ἀνάλωτον αὐτὴν ἐκ βίας ὑπάρχειν, ἐπερωτῆσαι εἰ οὐδ’ ὁ χρυσὸς τὸ τεῖχος ὑπερβῆναι δυνατός ἐστιν. ἦν γὰρ πεῖραν εἰληφὼς ὅτι τὰ τοῖς ὅπλοις ἀδύνατα χειρωθῆναι τῷ χρυσῷ ῥᾴδιόν ἐστι καταπολεμῆσαι. ἐγκατασκευάζων οὖν ἐν ταῖς πόλεσι προδότας διὰ τῆς δωροδοκίας καὶ τοὺς δεχομένους τὸ χρυσίον ξένους καὶ φίλους ὀνομάζων ταῖς πονηραῖς ὁμιλίαις διέφθειρε τὰ ἤθη τῶν ἀνθρώπων.
(Diodorus Siculus, Hist. 16.54)
Since the Athenians viewed with alarm the rising power of Philip, they came to the assistance of any people who were attacked by the king, by sending envoys to the cities and urging them to watch over their independence and punish with death those citizens who were bent on treason, and they promised them all that they would fight as their allies, and, after publicly declaring themselves the king’s enemies, engaged in an out-and-out war against Philip. The man who more than any other spurred them on to take up the cause of Hellas was the orator Demosthenes, the most eloquent of the Greeks of those times. Even his city was, however, unable to restrain its citizens from their urge toward treason, such was the crop, as it were, of traitors that had sprung up at that time throughout Hellas. Hence the anecdote that when Philip wished to take a certain city with unusually strong fortifications and one of the inhabitants remarked that it was impregnable, he asked if even gold could not scale its walls. For he had learned from experience that what could not be subdued by force of arms could easily be vanquished by gold. So, organizing bands of traitors in the several cities by means of bribes and calling those who accepted his gold “guests” and “friends,” by his evil communications he corrupted the morals of the people. (tr. Charles L. Sherman)