However much the capitalist mode of appropriation may seem to fly in the face of the original laws of commodity production, it nevertheless arises, not from a violation, but, on the contrary, from the application of these laws. Let us make this clear once more by briefly reviewing the consecutive phases of motion whose culminating point is capitalist accumulation. We saw, in the first place, that the original conversion of a sum of values into capital was achieved in complete accordance with the laws of exchange. One party to the contract sells his labor-power, the other buys it. The former receives the value of his commodity, whose use value – labor – is thereby alienated to the buyer. Means of production which already belong to the latter are then transformed by him, with the aid of labor equally belonging to him, into a new product which is likewise lawfully his. The value of the product includes: first, the value of the used-up means of production. Useful labor cannot consume these means of production without transferring their value to the new product, but, to be saleable, labor-power must be capable of supplying useful labor in the branch of industry in which it is to be employed. The value of the new product further includes: the equivalent of the value of labor-power together with a surplus-value. This is so because the value of labor-power – sold for a definite length of time, say a day, a week etc – is less than the value created by its use during that time. But the worker has received payment for the exchange-value of his labor-power and by so doing has alienated its use value – this being the case in every sale and purchase. The fact that this particular commodity, labor-power, possesses the peculiar use value of supplying labor, and therefore, of creating value, cannot affect the general law of commodity production. If, therefore, the magnitude of the value advanced in wages is not merely found again in the product, but is found there augmented by a surplus-value, this is not because the seller has been defrauded, for he has really received the value of his commodity; it is due solely to the fact that this commodity has been used up by the buyer. The law of exchange requires equality only between the exchange-values of the commodities given in exchange for one another. From the very outset, it presupposes even a difference between their use-values and it has nothing whatever to do with their consumption, which only begins after the deal is closed and executed. Thus the original conversion of money into capital is achieved in the most exact accordance with the economic laws of commodity production and with the right of property derived from them. Nevertheless, the result is: 1. That the product belongs to the capitalist and not to the worker 2. That the value of this product includes, besides the value of the capital originally advanced, a surplus-value which costs the worker labor but the capitalist nothing, and which nonetheless becomes the legitimate property of the capitalist 3. That the worker has retained his labor-power and can sell it anew if he can find a buyer. Simple reproduction is only the periodical repetition of this first operation; each time money is converted afresh into capital. Thus the law is not broken; on the contrary, it is merely enabled to operate continuously. [...] Nor does it matter if simple reproduction is replaced by reproduction on an extended scale, by accumulation. In the former case the capitalist squanders the whole surplus-value in dissipation, in the latter he demonstrates his bourgeois virtue by consuming only a portion of it and converting the rest into money. Marx, Capital, Volume 1 (Progress Publishers, 1887), p.413-414

To be sure, the matter looks quite different if we consider capitalist production in the uninterrupted flow of its renewal, and if, in place of the individual capitalist and the individual worker, we view in their totality, the capitalist class and the working class confronting each other. But in so doing we should be applying standards entirely foreign to commodity production. Only buyer and seller, mutually independent, face each other in commodity production. The relations between them cease on the day when the term stipulated in the contract they concluded expires. If the transaction is repeated, it is repeated as the result of a new agreement which has nothing to do with the previous one and which only by chance brings the same seller together again with the same buyer. If, therefore, commodity production, or one of its associated processes, is to be judged according to its own economic laws, we must consider each act of exchange by itself, apart from any connexion with the act of exchange preceding it and that following it. And since sales and purchases are negotiated solely between particular individuals, it is not admissible to seek here for relations between whole social classes. However long a series of periodical reproductions and preceding accumulations the capital functioning today may have passed through, it always preserves its original virginity. So long as the laws of exchange are observed in every single act of exchange the mode of appropriation can be completely revolutionised without in any way affecting the property rights which correspond to commodity production. These same rights remain in force both at the outset, when the product belongs to its producer, who, exchanging equivalent for equivalent, can enrich himself only by his own labour, and also in the period of capitalism, when social wealth becomes to an ever- increasing degree the property of those who are in a position to appropriate continually and ever afresh the unpaid labour of others. This result becomes inevitable from the moment there is a free sale, by the labourer himself, of labour-power as a commodity. But it is also only from then onwards that commodity production is generalised and becomes the typical form of production; it is only from then onwards that, from the first, every product is produced for sale and all wealth produced goes through the sphere of circulation. Only when and where wage labour is its basis does commodity production impose itself upon society as a whole; but only then and there also does it unfold all its hidden potentialities. To say that the supervention of wage labour adulterates commodity production is to say that commodity production must not develop if it is to remain unadulterated. To the extent that commodity production, in accordance with its own inherent laws, develops further, into capitalist production, the property laws of commodity production change into the laws of capitalist appropriation. Marx, Capital, Volume 1, p.414-415