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.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: de Quæst. Ev. l. ii. q. 34.