俱舍論疏 23.64

23.64

論「分謂分段至決擇分名」，此釋分名。一切聖道皆名決擇，此所順者唯是見道，故言分也。是故此名順決擇分。

The treatise says: "'Part' (bhāga) means portion ... the name 'aids to penetration.'" This explains the name 'part'. All noble paths are called penetration, and that which accords with this is solely the path of seeing; therefore, it is called a "part". Hence these are named "aids to penetration" (nirvedhabhāgīya).