俱舍論疏 14.36

14.36

論「即於爾時至立業道名」，釋業道也。《正理論》云「亦得名為根本業道。初防身語，暢思業故（解云：由如於人遊履於道易暢，諸身、語業道亦爾。思業遊暢義，同名為業道）。」

The treatise says: "At that very time […] the designation 'course of action' is established," explaining karmapatha. The Nyāyānusāra says: "It also obtains the designation of root course of action (maula-karmapatha). Because it initially guards body and speech, it fulfills intentional action. (The commentary explains: Just as it is easy for people to walk and tread along a path, so it is with courses of bodily and verbal action. The meaning of intentional action walking and traversing is identical, so it is called a course of action.)"