大般涅槃經集解 55.84

55.84

案僧亮曰：有為之法是因是果，故苦也；涅槃是果無因，故非苦也。僧宗曰：無生因也。寶亮曰：體是果者，了因之果也。

Sengliang comments: Saṃskṛta dharmas are both cause and fruit, and are therefore suffering; nirvāṇa is a fruit without a cause, and is therefore not suffering. Sengzong says: It is without a generative cause. Baoliang says: "Its essence is fruit" refers to the fruit of the revealing cause.