Plato, Laws 691c

ἐάν τις μείζονα διδῷ τοῖς ἐλάττοσι παρεὶς τὸ μέτριον, πλοίοις τε ἱστία καὶ σώμασιν τροφὴν καὶ ψυχαῖς ἀρχάς, ἀνατρέπεταί που πάντα, καὶ ἐξυβρίζοντα τὰ μὲν εἰς νόσους θεῖ, τὰ δʼ εἰς ἔκγονον ὕβρεως ἀδικίαν. τί οὖν δή ποτε λέγομεν; ἆρά γε τὸ τοιόνδε, ὡς οὐκ ἔστʼ, ὦ φίλοι ἄνδρες, θνητῆς ψυχῆς φύσις ἥτις ποτὲ δυνήσεται τὴν μεγίστην ἐν ἀνθρώποις ἀρχὴν φέρειν νέα καὶ ἀνυπεύθυνος,

If one neglects the rule of due measure, and gives things too great in power to things too small—sails to ships, food to bodies, offices of rule to souls—then everything is upset, and they run, through excess of insolence, some to bodily disorders, others to that offspring of insolence, injustice. What, then, is our conclusion? Is it not this? There does not exist, my friends, a mortal soul whose nature, when young and irresponsible, will ever be able to stand being in the highest ruling position upon earth without getting surfeited in mind with that greatest of disorders,