大般涅槃經集解 45.17

45.17

案僧亮曰：因果難知，甚深義也。佛性是因之深者，無我以下皆說中道也。僧宗曰：此第五辨修慧也。境不異前，但解力轉深耳。

Sengliang states: "Cause and fruit are difficult to know; this is the profound meaning. Buddhadhātu is the profound aspect of the cause; from 'non-self' onward, all speak of the middle path." Sengzong states: "This fifth clarifies the wisdom of cultivation. The cognitive sphere is not different from before, but the power of understanding becomes increasingly deep."