It's Cinco de Mayo and that means that we also have a birthday to celebrate. Luckily, there's considerable overlap:
In and for itself, the exchange of commodities implies no other relations of dependence than those which result from its own nature. On this assumption, labour-power can appear on the market as a commodity only if, and in so far as, its possessor, the individual whose labour-power it is, offers it for sale or sells it as a commodity. In order that its possessor may sell it as a commodity, he must have it at his disposal, he must be the free proprietor of his own labour-capacity, hence of his person. He and the owner of money meet in the market, and enter into relations with each other on a footing of equality as owners of commodities, with the sole difference that one is a buyer, the other a seller; both are therefore equal in the eyes of the law. For this relation to continue, the proprietor of labour-power must always sell it for a limited period only, for if he were to sell it in a lump, once and for all, he would be selling himself, converting himself from a free man into a slave, from an owner of a commodity into a commodity.
-- Karl Marx, Capital, Volume I
Trust me when I say that the German reads more fluidly. This translation is clear enough, but a little awkward and fussy. Anybody want to drive down to 4th Street tomorrow to see this description in action? We can get a late breakfast at Bette's afterward.