Indeed, just as frightened horses raise their necks up high, in the same way all those devotees of empty glory raise themselves above everything else, above cities, laws, ancestral custom, and the affairs of individual citizens. As they move from demagoguery to dictatorship, they subdue some of their neighbors as they try to make themselves superior and upright — and then they plan to enslave however so many minds remain naturally free and unenslaved.

[τῷ γὰρ ὄντι καθάπερ οἱ γαῦροι τῶν ἵππων τὸν αὐχένα μετέωρον ἐξάραντες, ὅσοι θιασῶται τῆς κενῆς δόξης εἰσίν, ἐπάνω πάντων ἑαυτοὺς ἱδρύουσι, πόλεων, νόμων, ἐθῶν πατρίων, τῶν παρ᾿ ἑκάστοις πραγμάτων· εἶτα ἀπὸ δημαγωγίας ἐπὶ δημαρχίαν βαδίζοντες καὶ τὰ μὲν τῶν πλησίον καταβάλλοντες, τὰ δὲ οἰκεῖα διανιστάντες καὶ παγίως ὀρθοῦντες, ὅσα ἐλεύθερα καὶ ἀδούλωτα φύσει φρονήματα]

Philo of Alexandria (AD c. 20-50) Hellenistic Jewish philosopher [Philo Judaeus]
On Dreams, That They Are God-Sent [Quod a Deo Mittantur Somnia or De Somniis], Book 2, ch. 12 [2.78-79] [tr. @sentantiq]
    (Source)

Alt. trans.: "In real truth, as spirited horses lift their necks high, so all who are companions of vain opinion place themselves above all things, above all cities, and laws, and national customs, and above all the circumstances which affect each individual of them. Then proceeding onwards from being demagogues to being leaders of the people, and overthrowing the things which belong to their neighbours, and setting up and establishing on a solid footing what belongs to themselves, that is to say, all such dispositions as are free and by nature impatient of slavery, they attempt to reduce these also under their power." [Yonge (1855)]