成唯識論了義燈 2.102

2.102

論：不撥為無但言非色。云何非色？《涅槃》第十八，六念中解。念戒者云：雖無形色，而可護持，雖無觸對，而可修習。第三十六諍論中云：無作戒者，非異色因，不作異色因果，是名無作戒。言非異色因者，非諸大造為因親造，不作異色因果者，非是大造因許果。故知無作，但依思立，應撿彼文。

The Śāstra: '[It] is not rejected as non-existent, but is merely said not to be form (rūpa).' How is it not form? In the eighteenth fascicle of the Nirvāṇa [Sūtra], it is explained under the six recollections. One who recollects the precepts says: 'Although it has no physical form or color, it can be preserved and maintained; although it has no tangible contact, it can be cultivated.' In the thirty-sixth [fascicle], on disputes, it says: 'The unmanifest precept is not a cause distinct from form, and it does not make the cause and effect of distinct form; this is called the unmanifest precept.' Stating that it is 'not a cause distinct from form' means that it is not directly produced with the great elements as its cause; stating that it 'does not make the cause and effect of distinct form' means that it is not an effect accepted as having the great elements as its cause. Hence we know that the unmanifest is posited merely on the basis of volition (cetanā); one should examine that text.