成唯識論述記 5.456

5.456

述曰：《顯揚》第一說四惑俱，故無法執，不言淨位有此識故。然今此論，不依《佛地》、無性《攝論》為證義文。本經、本論不言七識有淨，亦通無漏故。

The Commentary states: The first fascicle of the Prakaraṇāryavācā states that it is associated with four afflictions; therefore it lacks dharmagrāha, because it does not state that this consciousness exists in the pure state. However, the present treatise does not rely on the Buddhabhūmi[-sūtra-śāstra] or Asvabhāva's Mahāyānasaṃgraha[-upanibandhana] as textual authority for the doctrine. The root sūtras and root treatises do not state that the seventh consciousness has purity, nor that it extends to the uncontaminated.