首楞嚴義疏注經 8.242

8.242

謂住因緣智，引無分別最勝般若，令得現前。智現理現，故云無為真如性淨明露。此地證得無染淨真如，謂此真如本性無染，亦不可說後方淨故，斷麁相現行障，修習般若波羅蜜增勝。

This means that abiding in the cognition of cause and condition, one draws forth non-conceptual, supreme prajñā, causing it to become manifest. Cognition becomes manifest and principle becomes manifest; hence it is said, 'The unconditioned tathatā, its nature pure and clearly revealed.' On this ground, one realizes the tathatā free from defilement and purity, meaning that this tathatā is inherently without defilement, nor can it be said to become pure afterward; one severs the hindrance of coarse marks in active manifestation and cultivates the prajñā-pāramitā to supreme excellence.