成唯識論述記 7.639

7.639

述曰：非簡去所依之心，而心所獨能熏故。問：心王簡心所尚獨為所熏，心所簡心王獨能熏何所妨？答：心王有自在，自在獨所熏；心所不自在，非獨即能熏。

The Commentary states: Because mental factors cannot perfume alone when the mind that is their basis is set aside. Question: If the mental king, setting aside the mental factors, can still alone be the perfumed, what prevents the mental factors, setting aside the mental king, from alone being capable of perfuming? Answer: The mental king possesses sovereignty, and having sovereignty, it alone is the perfumed; mental factors lack sovereignty, and lacking independence, they cannot alone perfume.