The weapons with which the bourgeoisie felled feudalism to the ground are now turned against the bourgeoisie itself.

But not only has the bourgeoisie forged the weapons that bring death to itself; it has also called into existence the men who are to wield those weapons--the modern working class--the proletarians.

Manifesto of the Communist Party — Part 10

In proportion as the bourgeoisie, _i.e._, capital, is developed, in the same proportion is the proletariat, the modern working class, developed; a class of laborers, who live only so long as they find work, and who find work only so long as their labor increases capital. These laborers, who must sell themselves piecemeal, are a commodity, like every other article of commerce, and are consequently exposed to all the vicissitudes of competition, to all the fluctuations of the market.

Manifesto of the Communist Party — Part 10

Owing to the extensive use of machinery and to division of labor, the work of the proletarians has lost all individual character, and, consequently, all charm for the workman. He becomes an appendage of the machine, and it is only the most simple, most monotonous, and most easily acquired knack, that is required of him. Hence, the cost of production of a workman is restricted almost entirely to the means of subsistence that he requires for his maintenance, and for the propagation of his race. But the price of a commodity, and therefore also of labor, is equal, in the long run, to its cost of production. In proportion, therefore, as the repulsiveness of the work increases, the wage decreases. Nay, more, in proportion as the use of machinery and division of labor increase, in the same proportion the burden of toil also increases, whether by prolongation of the working hours, by increase of the work exacted in a given time, or by increased speed of the machinery, etc.

Manifesto of the Communist Party — Part 10

Modern industry has converted the little workshop of the patriarchal master into the great factory of the industrial capitalist. Masses of laborers, crowded into the factory, are organized like soldiers. As privates of the industrial army they are placed under the command of a perfect hierarchy of officers and sergeants. Not only are they slaves of the bourgeois class, and of the bourgeois State, they are daily and hourly enslaved by the machine, by the over-seer, and, above all, by the individual bourgeois manufacturer himself. The more openly this despotism proclaims gain to be its end and aim, the more petty, the more hateful and the more embittering it is.