Value, Price and Profit was a series of lectures made by Karl Marx to the First International Working Men's Association on June 20 and 27, 1865. It was later published as a book in 1898 by his daughter Eleanor Marx.
"At the same time, and quite apart from the general servitude involved in the wages system, the working class ought not to exaggerate to themselves the ultimate working of these everyday struggles. They ought not to forget that they are fighting with effects, but not with the causes of those effects; that they are retarding the downward movement, but not changing its direction; that they are applying palliatives, not curing the malady. They ought, therefore, not to be exclusively absorbed in these unavoidable guerilla fights incessantly springing up from the never ceasing encroachments of capital or changes of the market. They ought to understand that, with all the miseries it imposes upon them, the present system simultaneously engenders the material conditions and the social forms necessary for an economical reconstruction of society. Instead of the conservative motto: “A fair day's wage for a fair day's work!” they ought to inscribe on their banner the revolutionary watchword: “Abolition of the wages system!" -- Excerpt
Full series of lectures: Economic Manuscripts: Value, Price and Profit, Karl Marx 1865