Plato, Laws 874c

ἑλὼν κτείνῃ, καθαρὸς ἔστω· καὶ ἐὰν λωποδύτην ἀμυνόμενος ἀποκτείνῃ, καθαρὸς ἔστω· καὶ ἐὰν ἐλευθέραν γυναῖκα βιάζηταί τις ἢ παῖδα περὶ τὰ ἀφροδίσια, νηποινὶ τεθνάτω ὑπό τε τοῦ ὑβρισθέντος βίᾳ καὶ ὑπὸ πατρὸς ἢ ἀδελφῶν ἢ ὑέων· ἐάν τε ἀνὴρ ἐπιτύχῃ γαμετῇ γυναικὶ βιαζομένῃ, κτείνας τὸν βιαζόμενον ἔστω καθαρὸς ἐν τῷ νόμῳ· καὶ ἐάν τις πατρὶ βοηθῶν θάνατον, μηδὲν ἀνόσιον δρῶντι, κτείνῃ τινά, ἢ μητρὶ ἢ τέκνοις ἢ ἀδελφοῖς ἢ συγγεννήτορι τέκνων,

and if a man in self-defence slay a footpad, he shall be guiltless. The man who forcibly violates a free woman or boy shall be slain with impunity by the person thus violently outraged, or by his father or brother or sons. And should a man discover his wedded wife being violated, if he kills the violator he shall be guiltless before the law. And if a man slay anyone when warding off death from his father (when he is doing no wrong), or from his mother or children or brethren, or from the mother of his own children,