Lukáš 16:6

A debtor, as before, represents spiritual ideas that have been learned ("borrowed") but not yet taken to heart. What this debtor borrowed is extraordinary: "oil" represents the desire for good that comes from a love of the Lord; a "bath" (a unit of measurement translated in a variety of ways) represents true ideas that spring from a desire for good; and "100" represents a state of fullness or completeness.

So what happens when we apply the external religious ideas represented by the steward? The debtor enters a lower spiritual state (he "sits down"), one which is an intermediate step ("50") to the 100 baths of oil. But rather than remaining a debtor, he "writes" it, meaning it is inscribed on his heart, and permanent.