Plato, Laws 829a

αὐτήν, καθάπερ ἕνα ἄνθρωπον, ζῆν εὖ· τοῖς δὲ εὐδαιμόνως ζῶσιν ὑπάρχειν ἀνάγκη πρῶτον τὸ μήθʼ ἑαυτοὺς ἀδικεῖν μήτε ὑφʼ ἑτέρων αὐτοὺς ἀδικεῖσθαι. τούτοιν δὲ τὸ μὲν οὐ πάνυ χαλεπόν, τοῦ δὲ μὴ ἀδικεῖσθαι κτήσασθαι δύναμιν παγχάλεπον, καὶ οὐκ ἔστιν αὐτὸ τελέως σχεῖν ἄλλως ἢ τελέως γενόμενον ἀγαθόν· ταὐτὸν δὴ τοῦτο ἔστι καὶ πόλει ὑπάρχειν, γενομένῃ μὲν ἀγαθῇ βίος εἰρηνικός, πολεμικὸς δὲ ἔξωθέν τε καὶ ἔνδοθεν, ἂν ᾖ κακή. τούτων δὲ ταύτῃ σχεδὸν ἐχόντων,

like an individual, ought to lead a good life. But for a good and blessed life, the first requisite is neither to do wrong oneself nor to suffer wrong from others. Of these, the former is not very hard, but it is very hard to secure immunity from suffering wrong; indeed, it is impossible to gain this perfectly, except by becoming perfectly good. So likewise a State may obtain a life of peace if it becomes good, but if bad, a life of war both abroad and at home. This being so, all men must train for war