"A larger part of their own surplus product, always increasing and continually transformed into additional capital, comes back to them in the shape of means of payment, so that they can extend the circle of their enjoyments; can make some additions to their consumption funds of clothes, furniture, &c., and can lay by a small reserve-funds of money. But just as little as better clothing, food, and treatment, and a larger peculium, do away with the exploitation of the slave, so little do they set aside that of the worker. A rise in the price of labour, as a consequence of accumulation of capital, only means in fact, that the length and weight of the golden chain the wage-worker has already forged for himself, allow of a relaxation of the tension of it." Chapter 25, p 579-580, Lawrence and Wishart edition.
Marx does write about the role of credit in driving speculation and fictitious capital leading to bankruptcies in Volume III, and he writes about all kinds of credit notes (including in one throwaway comment, personal credit, but from the context it seems clear that it is personal credit extended to capitalists, p 403). But his main example of credit's role in the business crisis of 1845-47 is dealing with credit notes given on cargos of cotton goods exported to the Far East, which turned out to be unsupported. (Interestingly the crisis was avoided by the suspension of the Banking Act limiting the amount of fiat money the Bank of England could print, Marx says, p 408)
The bogus Marx quote:
"Owners of capital will stimulate the working class to buy more and more of expensive goods, houses and technology, pushing them to take more and more expensive credits, until their debt becomes unbearable. The unpaid debt will lead to bankruptcy of banks, which will have to be nationalised, and the State will have to take the road which will eventually lead to communism. "