首楞嚴義疏注經 4.234

4.234

The realm is subtle and wondrous, unfathomable by mind or speech. Ordinary beings cling to phenomena; partial, lesser practitioners stagnate in emptiness; both are of the mind of known objects, unable to reach this realm. Thus the Perfect Enlightenment Sūtra states: 'Even the realm perfected by all the śrāvakas, in which body, mind, and language are all entirely cut off, can never reach the nirvāṇa manifested through their own personal realization; how much less could one use a conceptualizing mind to gauge the Tathāgata's realm of perfect enlightenment? It is like taking a firefly's light to burn Mount Sumeru—it can never ignite it. Entering the Tathāgata's great sea of tranquil extinction with a mind of cyclic existence producing views of cyclic existence, one can never reach it.'