Plato, Laws 867d

θυμῷ μέν, μετʼ ἐπιβουλῆς δὲ κτείνας τὰ μὲν ἄλλα κατὰ τὸν πρόσθεν αὖ, τρία δὲ ἔτη, καθάπερ ἅτερος ἔφευγεν τὰ δύο, φευγέτω, μεγέθει θυμοῦ πλείω τιμωρηθεὶς χρόνον. καθόδου δὲ πέρι τούτοις ὧδε ἔστω. χαλεπὸν μὲν ἀκριβῶς νομοθετεῖν· ἔστι γὰρ ὅτε τούτοιν ὁ τῷ νόμῳ ταχθεὶς χαλεπώτερος ἡμερώτερος ἄν, ὁ δὲ ἡμερώτερος χαλεπώτερος ἂν εἴη, καὶ τὰ περὶ τὸν φόνον ἀγριωτέρως ἂν πράξειεν, ὁ δὲ ἡμερωτέρως· ὡς

And he that slays in passion and with deliberate intent shall be treated in other respects like the former, but shall be exiled for three years—instead of two, like the other,—receiving a longer period of punishment because of the greatness of his passion. As regards the return home, in such cases it shall be on this wise. (It is a difficult matter to legislate for with exactness; for sometimes the more dangerous of the two murderers in the eye of the law might prove the more gentle and the gentler the more dangerous, and the latter might have committed the murder more savagely, the former more gently; though as a rule matters turn out in the way we have stated: