Marx maintains that labor in capitalism has a “double character”: it is both “concrete labor” and “abstract labor.” “Concrete labor” refers to the fact that some form of what we consider laboring activity mediates the interactions of humans with nature in all societies. “Abstract labor” does not  simply refer to concrete labor in general, but is a very different sort of category. It signifies that, in capitalism, labor also has a unique social function that is not intrinsic to laboring activity as such: it mediates a new form of social
interdependence.

Let me elaborate: In a society in which the commodity is the basic structuring category of the whole, labor and its products are not socially distributed by traditional ties, norms, or overt relations of power and domination—that is, by manifest social relations—as is the case in other societies. Instead, labor itself replaces those relations by serving as a kind of quasi-objective means by which the products of  others are acquired. A new form of interdependence comes into being where people do not consume what they produce, but where, nevertheless, their own labor or labor-products function as a quasi-objective, necessary means of obtaining
the products of others. In serving as such a means, labor and its products in effect preempt that function on the part of  manifest social relations.