Plato, Laws 867a

θυμῷ γεγονότας, μεταξὺ δέ που τοῦ τε ἑκουσίου καὶ ἀκουσίου δικαιότατʼ ἂν λεγομένους. οὐ μὴν ἀλλʼ εἰκών ἐσθʼ ἑκάτερος· ὁ μὲν τὸν θυμὸν φυλάττων καὶ οὐκ ἐκ τοῦ παραχρῆμα ἐξαίφνης ἀλλὰ μετὰ ἐπιβουλῆς ὕστερον χρόνῳ τιμωρούμενος ἑκουσίῳ ἔοικεν, ὁ δὲ ἀταμιεύτως ταῖς ὀργαῖς καὶ ἐκ τοῦ παραχρῆμα εὐθὺς χρώμενος ἀπροβουλεύτως ὅμοιος μὲν ἀκουσίῳ, ἔστι δὲ οὐδʼ οὗτος αὖ παντάπασιν ἀκούσιος ἀλλʼ εἰκὼν ἀκουσίου.

both as a rule done in passion, and most properly described as lying midway between the voluntary and the involuntary. None the less, each of these kinds tends to resemble one or other of these contraries; for the man who retains his passion and takes vengeance, not suddenly on the spur of the moment, but after lapse of time, and with deliberate intent, resembles the voluntary murderer; whereas the man who does not nurse his rage, but gives way to it at once on the spur of the moment and without deliberate intent, has a likeness to the involuntary murderer; yet neither is he wholly involuntary, but bears a resemblance thereto.