“The people quickly fall into slavery through the good intentions of their betters”
ἀπὸ τούτων τοίνυν τῶν ἀγαθῶν τάχιστ’ ἂν ὁ δῆμος εἰς δουλείαν καταπέσοι.
This is from the Athenaion Politeia (“Constitution of the Athenians”), which may or may not be by Aristotle but is certainly not by Xenophon.