“The slave and master in one skin
Is all your history, no more, no less”

"On Court-Influence" (January 3/January 10, 1818)
Political Essays (1819)

Maxim 657
Sentences, The Moral Sayings of Publius Syrus, a Roman Slave

Source: No Treason (1867–1870), No. VI: The Constitution of No Authority, p. 24; the first sentence here is widely paraphrased as: A man is no less a slave because he is allowed to choose a new master once in a term of years.
Context: A man is none the less a slave because he is allowed to choose a new master once in a term of years. Neither are a people any the less slaves because permitted periodically to choose new masters. What makes them slaves is the fact that they now are, and are always hereafter to be, in the hands of men whose power over them is, and always is to be, absolute and irresponsible.
The right of absolute and irresponsible dominion is the right of property, and the right of property is the right of absolute, irresponsible dominion. The two are identical; the one necessarily implying the other. Neither can exist without the other. If, therefore, Congress have that absolute and irresponsible lawmaking power, which the Constitution — according to their interpretation of it — gives them, it can only be because they own us as property. If they own us as property, they are our masters, and their will is our law. If they do not own us as property, they are not our masters, and their will, as such, is of no authority over us.
But these men who claim and exercise this absolute and irresponsible dominion over us, dare not be consistent, and claim either to be our masters, or to own us as property. They say they are only our servants, agents, attorneys, and representatives. But this declaration involves an absurdity, a contradiction. No man can be my servant, agent, attorney, or representative, and be, at the same time, uncontrollable by me, and irresponsible to me for his acts. It is of no importance that I appointed him, and put all power in his hands. If I made him uncontrollable by me, and irresponsible to me, he is no longer my servant, agent, attorney, or representative. If I gave him absolute, irresponsible power over my property, I gave him the property. If I gave him absolute, irresponsible power over myself, I made him my master, and gave myself to him as a slave. And it is of no importance whether I called him master or servant, agent or owner. The only question is, what power did I put into his hands? Was it an absolute and irresponsible one? or a limited and responsible one?

Source: The End of History and the Last Man

Source: Wild Seed (1980), Chapter 1 (p. 11)

IV, 3
Variant translation: The good man, though a slave, is free; the wicked, though he reigns, is a slave, and not the slave of a single man, but — what is worse — the slave of as many masters as he has vices.
The City of God (early 400s)
Context: 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.”

Ils etaient plus que rois; ils sont moindres qu'esclaves.
Sertorius, act III, scene i
Sertorius describes Roman citizens after they had fallen under tyranny.
Sertorius (1662)

"Of Monarchy," p. 120
Against Rousseau (1795)