In message <p0621020dbeabd4b2b6e8@[192.168.1.100]> lbo-talk@lbo-talk.org writes:
> There's a passage in which Marx describes competition as the force 
> that commands individual capitalists to "March! March!" Anyone know 
> where it is?

There's this bit of the Grundrisse, which might be the bit you're thinking of:

http://www.marxists.org/archive/marx/works/1857/grundrisse/ch08.htm

*** (In competition this inner tendency of capital appears as a compulsion exercised over it by alien capital, which drives it forward beyond the correct proportion with a constant march, march! Free competition, as Mr Wakefield correctly sniffs out in his commentary on Smith, has never yet been developed by the economists, no matter how much they prattle about it, and [no matter] how much it is the basis of the entirety of bourgeois production, production resting on capital. It has been understood only negatively: i.e. as negation of monopolies, the guild system, legal regulations etc. As negation of feudal production. But it also has to be something for itself, after all, since a mere 0 is an empty negation, abstraction, from a barrier which immediately arises again e.g. in the form of monopoly, natural monopolies etc. Conceptually, competition is nothing other than the inner nature of capital, its essential character, appearing in and realized as the reciprocal interaction
  of many capitals with one another, the inner tendency as external necessity.) ***


Chris