Thucydides 3.10.1 (tr. Charles Forster Smith):
We will first discuss the question of justice
and rectitude, especially as we are seeking an alliance,
for we know that neither does friendship between
men prove lasting, nor does a league between states
come to aught, unless they comport themselves with
transparent honesty of purpose towards one another
and in general are of like character and way of
thinking; for differences in men's actions arise from
the diversity of their convictions.
περὶ γὰρ τοῦ δικαίου καὶ ἀρετῆς πρῶτον, ἄλλως τε καὶ ξυμμαχίας δεόμενοι, τοὺς λόγους ποιησόμεθα, εἰδότες οὔτε φιλίαν ἰδιώταις βέβαιον γιγνομένην οὔτε κοινωνίαν πόλεσιν ἐς οὐδέν, εἰ μὴ μετ ̓ ἀρετῆς δοκούσης ἐς ἀλλήλους γίγνοιντο καὶ τἆλλα ὁμοιότροποι εἶεν· ἐν γὰρ τῷ διαλλάσσοντι τῆς γνώμης καὶ αἱ διαφοραὶ τῶν ἔργων καθίστανται.
A.W. Gomme ad loc.:
