The dominion of bad men is hurtful chiefly to themselves who rule, for they destroy their own souls by greater license in wickedness; while those who are put under them in service are not hurt except by their own iniquity. For to the just all the evils imposed on them by unjust rulers are not the punishment of crime, but the test of virtue. Therefore the good man, although he is a slave, is free; but the bad man, even if he reigns, is a slave, and that not of one man, but, what is far more grievous, of as many masters as he has vices; of which vices when the divine Scripture treats, it says, For of whom any man is overcome, to the same he is also the bond-slave.

IV, 3 - The City of God (early 400s)