俱舍論疏 16.13

16.13

論「此非白言至性相違故」，釋疑難也。非黑言是了義說，非白言是密意說，以不能招白異熟故，經密意說名非白業。准經及本論，是純白法也。

The Śāstra says: "This phrase 'not bright' […] because their natures contradict"—this resolves a doubt and objection. The statement "not dark" is of definitive meaning, whereas the statement "not bright" is of intentional meaning: because it cannot invite a bright maturation, the sūtra intentionally states that it is "not bright karma". According to the sūtra and the root treatise, it is a purely bright phenomenon.