俱舍論疏 3.72

3.72

論「謂在見道至名未知當知」，此釋初無漏根名也。智名為知，忍非知故。在見道中苦法智忍位，有八諦未知當知行轉，至苦法智位有七未知當知行，乃至道類忍位有色、無色道諦未知當知行故，故十五心皆名未知當知根也。

Regarding the passage in the treatise, “Namely, on the path of seeing … up to … is named ‘will come to know what is not yet known’”: This explains the name of the first undefiled faculty. Knowledge (jñāna) is called ‘knowing’ (jñā), whereas receptivity (kṣānti) is not knowing. On the path of seeing, at the stage of the receptivity to the dharma-knowledge of suffering, there is an activity [of mind regarding] ‘will come to know what is not yet known’ for the eight truths; at the stage of the dharma-knowledge of suffering, there is an activity of ‘will come to know what is not yet known’ for the seven [truths], and so on up to the receptivity to the subsequent-knowledge of the path, where there is an activity of ‘will come to know what is not yet known’ for the truth of the path in the form and formless realms. Therefore, all fifteen moments of mind are called the faculty of one who will come to know what is not yet known.