The Republic by Plato Part 9 Page 67

ought to be the servant of the best, in whom the Divine rules; not, as Thrasymachus supposed, to the injury of the servant, but because every one had better be ruled by divine wisdom dwelling within him; or, if this be impossible, then by an external authority, in order that we may be all, as far as possible, under the same government, friends and equals.

True, he said.

And this is clearly seen to be the intention of the law, which is the ally of the whole city; and is seen also in the authority which we exercise over children, and the refusal to let them be free until we have established in them a principle analogous to the constitution of a state, and by cultivation of this higher element have set up in their hearts a guardian and ruler like our own, and when this is done they may go their ways.