大方廣佛華嚴經隨疏演義鈔 37.41

37.41

疏「若取知能知寂」者，此即用於禪宗知識之偈。偈中具云「若以知知寂，此非無緣知，如手執如意，非無如意手。若以自知知，亦非無緣知，如手作於拳，非是不拳手。亦不知知寂，亦不自知知，不可謂無知，自性了然故，不同於木石。手不執如意，亦不自作拳，不可謂無手，以手安然故，不同於木石。」斯為禪宗之妙，故今用之而復小異，以彼但顯無緣真智以為真道。若奪之者，但顯本心不隨妄心，未有智慧照了心源，故云「故須能所平等，等不失照」，為無知之知。此知知於空寂無生如來藏性，方為妙耳。

As for the commentary's phrase “if one takes knowing as being able to know quiescence”: this utilizes a verse of a Chan spiritual master. The verse fully states: “If one knows quiescence by means of knowing, this is not objectless knowing; like a hand holding a ruyi scepter, it is not a hand without a ruyi scepter. If one knows by knowing oneself, this is also not objectless knowing; like a hand making a fist, it is not an unfisted hand. Neither knowing quiescence through knowing, nor knowing oneself through knowing, yet it cannot be called non-knowing, because intrinsic nature is clearly distinct, unlike wood and stone. The hand does not hold a ruyi scepter, nor does it make a fist of itself, yet it cannot be called non-hand, because the hand is at ease, unlike wood and stone.” This is the marvel of the Chan school. Therefore it is now used here with a slight difference, because that verse merely reveals objectless true cognition as the true Path. If one negates it, it merely reveals that the fundamental mind does not follow the deluded mind, but does not yet possess the wisdom that illuminates and comprehends the source of the mind. Hence it says: “Therefore subject and object must be equal, and while equal they do not lose illumination,” which is the knowing of non-knowing. Only when this knowing knows the empty, quiescent, unarisen tathāgatagarbha nature is it truly marvelous.