大方廣佛華嚴經隨疏演義鈔 8.32

8.32

疏「四頓教」等者，初正立、次釋名、後解妨。今初。言「一念不生即是佛」者，即心本是佛體，妄起故為眾生。一念妄心不生，何為不得名佛？故達摩碑云「心有也，曠劫而滯凡夫；心無也，剎那而登正覺。」下經云「法性本空寂，無取亦無見。性空即是佛，不可得思量。」

Regarding the commentary's "Fourth, the sudden teaching" and so forth: first, directly establishing it; next, explaining the name; finally, resolving objections. Now, the first: as for "a single thought not arising is itself the Buddha," this means the mind is originally the essence of the Buddha; it is because delusion arises that it becomes a sentient being. If not even a single thought of the deluded mind arises, why would it not be named Buddha? Thus the Stele of Bodhidharma states: "When the mind exists, for vast eons one stagnates as an ordinary being; when the mind is absent, in a kṣaṇa one ascends to correct awakening." A later part of the sūtra states: "The dharmatā is originally empty and tranquil, / without grasping and without viewing. / Emptiness of nature is itself the Buddha; / it cannot be conceived."