俱舍論疏 2.121

2.121

論「眼等六識至如意界說」，此由六識轉為意故，如釋意界，六識亦爾。

The Śāstra says: "The six consciousnesses, eye-[consciousness] and the rest... are explained like the mano-dhātu." Because the six consciousnesses transform into the manas, just as the mano-dhātu is explained, so too are the six consciousnesses.