首楞嚴義疏注經 9.116

9.116

身心滅盡者，色身必盡，其心若盡非盡，妄謂為盡。定性現前者，有定果色。若無此色，四心何依？故知有也。

'Body and mind are completely extinguished': the physical body must be exhausted; their mind is as if exhausted yet not exhausted, but they falsely deem it exhausted. 'The nature of concentration appears before them': there is concentration-resultant form. If there were no such form, upon what would the four minds rely? Therefore we know it exists.