Plato, Laws 867b

διὸ χαλεποὶ διορίζειν οἱ τῷ θυμῷ πραχθέντες φόνοι, πότερον ἑκουσίους αὐτοὺς ἤ τινας ὡς ἀκουσίους νομοθετητέον, βέλτιστον μὴν καὶ ἀληθέστατον εἰς εἰκόνα μὲν ἄμφω θεῖναι, τεμεῖν δὲ αὐτὼ χωρὶς τῇ ἐπιβουλῇ καὶ ἀπροβουλίᾳ, καὶ τοῖς μὲν μετʼ ἐπιβουλῆς τε καὶ ὀργῇ κτείνασιν τὰς τιμωρίας χαλεπωτέρας, τοῖς δὲ ἀπροβουλεύτως τε καὶ ἐξαίφνης πρᾳοτέρας νομοθετεῖν· τὸ γὰρ εἰκὸς μείζονι κακῷ μειζόνως, τὸ

Thus murders done in passion are difficult to define,—whether one should treat them in law as voluntary or involuntary. The best and truest way is to class them both as resemblances, and to distinguish them by the mark of deliberate intent or lack of intent, and to impose more severe penalties on those who slay with intent and in anger, and milder penalties on those who do so without intent and on a sudden. For that which resembles a greater evil must be more heavily punished, that which resembles a lesser evil