The primary source is Lord Pentland's essay of that title, and it's freely available on the Gurdjieff Foundation's site: — it's a reflection on the relationship of religion to money, arguing that money originated as a symbol replacing food in sacrificial communion rituals, binding loyalty between individuals and covenant with the deity, and that this significance has eroded until money now functions almost exclusively on a material level. Worth reading in full — the essay's actual argument (money as degraded sacrament, transactions as depersonalized former bonds of loyalty) is considerably more traditional than the entrepreneurial gloss the quote gets when it circulates alone, which is itself a neat little instance of Horowitz's own warning about ideas torn from context. The closing line he uses in the chapter ("Rich people think passively, yes?") comes from Pentland's group-meeting exchanges collected in Exchanges Within (1997), which Horowitz also cites in chapter twelve.