And thus every man, by consenting with others to make one body politic under one government, puts himself under an obligation, to every one of that society, to submit to the determination of the majority, and to be concluded by it; or else this original compact, whereby he with others incorporates into one society, would signify nothing, and be no compact, if he be left free, and under no other ties than he was in before in the state of nature. For what appearance would there be of any compact? what new engagement if he were no farther tied by any decrees of the society, than he himself thought fit, and did actually consent to? This would be still as great a liberty, as he himself had before his compact, or any one else in the state of nature hath, who may submit himself, and consent to any acts of it if he thinks fit.
For if the consent of the majority shall not, in reason, be received as the act of the whole, and conclude every individual; nothing but the consent of every individual can make any thing to be the act of the whole: but such a consent is next to impossible ever to be had, if we consider the infirmities of health, and avocations of business, which in a number, though much less than that of a common-wealth, will necessarily keep many away from the public assembly. To which if we add the variety of opinions, and contrariety of interests, which unavoidably happen in all collections of men, the coming into society upon such terms would be only like Cato’s coming into the theatre, only to go out again. Such a constitution as this would make the mighty Leviathan of a shorter duration, than the feeblest creatures, and not let it outlast the day it was bom in: which cannot be supposed, till we can think, that rational creatures should desire and constitute societies only to be dissolved: for where the majority cannot conclude the rest, there they cannot act as one body, and consequently will be immediately dissolved again.
Whosoever therefore out of a state of nature unite into a community, must be understood to give up all the power, necessary to the ends for which they unite into society, to the majority of the community, unless they expresly agreed in any number greater than the majority. And this is done by barely agreeing to unite into one political society, which is all the compact that is, or needs be, between the individuals, that enter into, or make up a commonwealth. And thus that, which begins and actually constitutes any political society, is nothing but the consent of any number of freemen capable of a majority to unite and incorporate into such a society. And this is that, and that only, which did, or could give beginning to any lawful government in the world.
Source: John Locke, Second Treatise on Government, Ch. 8.