仁王般若經疏 1.25

1.25

有為功德下，第四歎德。有為功德無為功德者，有為舉智德，無為是舉斷德。若約境，道諦是有為，滅諦是無為。施功名功，歸己曰德，故名功德也。

From "conditioned merits" onward is the fourth part, praising virtues. As for "conditioned merits, unconditioned merits": conditioned brings out the virtue of wisdom, while unconditioned brings out the virtue of elimination. If analyzed in terms of the cognitive object, the truth of the path is conditioned, and the truth of cessation is unconditioned. Exerting effort is called merit (gōng); returning to oneself is called virtue (dé); hence they are called "merits" (gōngdé).