俱舍論疏 23.65

23.65

論「此四為緣至順決擇分」，釋順名也。此四為緣，引決擇一分，亦能順益決擇一分故，故此四種得順彼名。

The treatise says: "Because these four serve as conditions ... aids to penetration." This explains the name 'aiding' (anukūla). Because these four serve as conditions to induce one part of penetration, and are also able to benefit and conform to one part of penetration, these four kinds receive the name of conforming to that.