大般涅槃經集解 54.57

54.57

案僧亮曰：第二問性義也。僧宗曰：此問因性也。謂不改之義可得在果，而因中以何理而稱性耶？寶亮曰：責所以因果性體，有何所以得受性名耶？

Sengliang says: The second asks about the meaning of 'nature'. Sengzong says: This asks about the causal nature. That is, the meaning of being unchanging can obtain in the fruit, but by what principle is it called 'nature' in the cause? Baoliang says: He demands the reason for the essences of the natures of cause and effect: for what reason do they receive the name 'nature'?