Quotes by Subject:

Leadership

He who is not a good servant will not be a good master. - Plato.

He who is to be a good ruler must have first been ruled. – Aristotle.

They should rule who are able to rule best. – Aristotle.

What you cannot enforce, do not command. – Socrates.

When the tyrant has disposed of foreign enemies by conquest or treaty, and there is nothing more to fear from them, then he is always stirring up some war or other, in order that the people may require a leader. - Plato.