In its beginnings, the credit system sneaks in as a modest helper of accumulation and draws by invisible threads the money resources scattered all over the surface of society into the hands of individual or associated capitalists. But soon it becomes a new and formidable weapon in the competitive struggle, and finally it transforms itself into an immense social mechanism for the centralisation of capitals.

Vol. I, Ch. 25, Section 2, pg. 687. - Das Kapital (Buch I) (1867)