Second Treatise of Civil Government John Locke (1690)
Sec.22. THE natural liberty of man is to be free from any superior power on earth, and not to be under the will or legislative authority of man, but to have only the law of nature for his rule. The liberty of man, in society, is to be under no other legislative power, but that established, by consent, in the commonwealth; nor under the dominion of any will, or restraint of any law, but what that legislative shall enact, according to the trust put in it. Freedom then is not what Sir Robert Filmer tells us, Observations, A. 55. a liberty for every one to do what he lists, to live as he pleases, and not to be tied by any laws: but freedom of men under government is, to have a standing rule to live by, common to every one of that society, and made by the legislative power erected in it; a liberty to follow my own will in all things, where the rule prescribes not; and not to be subject to the inconstant, uncertain, unknown, arbitrary will of another man: as freedom of nature is, to be under no other restraint but the law of nature.
Sec.23. This freedom from absolute, arbitrary power, is so necessary to, and closely joined with a man's preservation, that he cannot part with it, but by what forfeits his preservation and life together: for a man, not having the power of his own life, cannot, by compact, or his own consent, enslave himself to any one, nor put himself under the absolute, arbitrary power of another, to take away his life, when he pleases. No body can give more power than he has himself; and he that cannot take away his own life, cannot give another power over it. Indeed, having by his fault forfeited his own life, by some act that deserves death; he, to whom he has forfeited it, may (when he has him in his power) delay to take it, and make use of him to his own service, and he does him no injury by it: for, whenever he finds the hardship of his slavery outweigh the value of his life, it is in his power, by resisting the will of his master, to draw on himself the death he desires.
Sec.24. This is the perfect condition of slavery, which is nothing else, but the state of war continued, between a lawful conqueror and a captive: for, if once compact enter between them, and make an agreement for a limited power on the one side, and obedience on the other, the state of war and slavery ceases, as long as the compact endures: for, as has been said, no man can, by agreement, pass over to another that which he hath not in himself, a power over his own life.
I confess, we find among the Jews, as well as other nations, that men did sell themselves; but, it is plain, this was only to drudgery, not to slavery: for, it is evident, the person sold was not under an absolute, arbitrary, despotical power: for the master could not have power to kill him, at any time, whom, at a certain time, he was obliged to let go free out of his service; and the master of such a servant was so far from having an arbitrary power over his life, that he could not, at pleasure, so much as maim him, but the loss of an eye, or tooth, set him free, Exod. xxi.