Plato, Laws 871a

νόμον ὑμνεῖν, ἀπειθοῦντι δὲ νόμος ὅδε εἰρήσθω τῇ γραφῇ· ὃς ἂν ἐκ προνοίας τε καὶ ἀδίκως ὁντιναοῦν τῶν ἐμφυλίων αὐτόχειρ κτείνῃ, πρῶτον μὲν τῶν νομίμων εἰργέσθω, μήτε ἱερὰ μήτε ἀγορὰν μήτε λιμένας μήτε ἄλλον κοινὸν σύλλογον μηδένα μιαίνων, ἐάντε τις ἀπαγορεύῃ τῷ δράσαντι ταῦτα ἀνθρώπων καὶ ἐὰν μή—ὁ γὰρ νόμος ἀπαγορεύει καὶ ἀπαγορεύων ὑπὲρ πάσης τῆς πόλεως ἀεὶ φαίνεταί τε καὶ φανεῖται

but to the disobedient this is the law which shall be stated in the written code:—Whosoever of deliberate intent and unjustly slays with his own hand any of the tribesmen shall, in the first place, be debarred from the lawful assemblies, and shall not defile either temples or market or harbors or any other place of meeting, whether or not any person warns off the doer of such deeds—for he is warned off by the law, which is, and always will continue, warning him thus publicly, on behalf of the whole State; and the man who fails to prosecute him when he ought,