Luke 16:6

16:6 The manager may simply have been dishonest, but Jews were forbidden to take usury and one way around the regulation was to overcharge. The man might have borrowed four hundred gallons of oil and had the bill made out for eight hundred, the extra being the equivalent of a high rate of interest. By significantly reducing the amount of interest the debtor owed, the manager would have obliged the debtor to assist him personally (v. 4), at least for a time, without diminishing the principal owed to his own master.