成唯識論述記 6.229

6.229

述曰：三外難言，此由未了彼心淨言。若淨體即是心，持業釋者，信應非心所，淨即心故。若淨體非即心，令心淨者，心之淨故，依依士釋第三轉聲。慚等何別？亦令心淨故。若心俱淨法，隣近釋者，淨與心俱故。為難同令淨，亦慚等無別。

The Commentary states: The third is the external objection, stating: this still has not clarified that statement "purification of the mind." If the substance of purification is itself mind, being a karmadhāraya compound, faith should not be a mental factor, because purification would itself be the mind. If the substance of purification is not itself mind, but makes the mind pure—"the purification of the mind"—it relies on a tatpuruṣa compound in the instrumental case (third case inflection). How does it differ from shame (hrī) and the like? For they also make the mind pure. If it means pure phenomena accompanying the mind, being a neighboring-attributive compound (upamānopameya / samīpatā compound), it would be because purification accompanies the mind. The objection regarding making [the mind] pure applies equally, and it would likewise not differ from shame and the like.