The Histories by Herodotus p.367: The Benefits of Democracy (5.78)

 (Commonplace Book)

From The Histories by Herodotus 

(In this passage, Herodotus has just gotten done describing the military victories of Athens after Athens over-throws its tyrant and re-establishes its democracy.  Before Athens had been militarily weak, but now they are winning battles again.  Herodotus attributes the military victories to the fact that Athens is now democratic.)

So Athens came to flourish--and to make manifest how important it is for everyone in a city to have an equal voice, not just on one level but on all.  For although the Athenians, while subjects of a tyrant, had been no more proficient in battle than any of their neighbors, they emerged as supreme by far once liberated from tyranny.  This is proof enough that the downtrodden will never willingly pull their weight, since their labours are all in the service of a master--whereas free men, because they have a stake in their own exertions, will set to them with enthusiasm.