Marx is talking about a specific bourgeois ideology of asceticism, the ideology which says abstinence is the source of wealth; that abstinence from consumption and satisfaction of one’s personal wants is how profit is made. Therefore when a capitalist profits, it is through their own personal abstinence, and they morally deserve the profits after having denied themself. Conversely, from this view, the working class has given in to those baser human needs, when they ought to be abstaining from those needs in order to prosper. This argument persists today in the conservative complaints about millennials buying avocado toast and fancy coffee.

If abstinence is the source of wealth, then the sum of that wealth is the sum of one’s self-denial. The resulting hoard of money is the objectification of the life not lived, with its own separate (alienated) existence as cold, hard cash.