俱舍論疏 16.4

16.4

"The Śāstra says: […] speaks of the four: dark-dark, and so forth"—this explains the intention in establishing the four karmas. "The nature of the karma and the fruit differ" refers to the three karmas: dark-dark, and so forth. "The antidoted and the antidote are distinct": defiled karma is the antidoted, and undefiled is the antidote. "Nature" is intrinsic substance, and "category" is variety; because nature and category differ, they are divided into four karmas.