This is my favourite summary of the parable:
He is no fool who gives what he cannot keep to gain that which he cannot lose.—Jim Elliot (October 28, 1949 journal entry)
It refers to the pivotal verse:
And I tell you, make friends for yourselves by means of unrighteous wealth, so that when it fails they may receive you into the eternal dwellings.—Luke 16:9 (ESV)