Augustine of Hippo
Catena Aurea · Lukasevangelium 16
And the lord commended the unjust steward, because he had done wisely: for the children of this world are in their generation wiser than the children of light. And I say unto you, Make to yourselves friends of the mammon of unrighteousness; that, when ye fail, they may receive you into everlasting habitations. He that is faithful in that which is least is faithful also in much: and he that is unjust in the least is unjust also in much. If therefore ye have not been faithful in the unrighteous mammon, who will commit to your trust the true riches? And if ye have not been faithful in that which is another man’s, who shall give you that which is your own? No servant can serve two masters: for either he will hate the one, and love the other; or else he will hold to the one, and despise the other. Ye cannot serve God and mammon.
(de Quæst. Ev. l. ii. q. 34.) Or the riches of unrighteousness are so called, because they are not riches except to the unrighteous, and such as rest in their hopes and the fulness of their happiness. But when these things are possessed by the righteous, they have indeed so much money, but no riches are theirs but heavenly and spiritual.