大般涅槃經集解 30.18

30.18

案僧亮曰：第三，舉所修善因也。因既是善，理有樂果，故以因為證。寶亮曰：第三難，以善是樂因，故知不應無樂。

Sengliang comments: Third, he cites the cultivated wholesome cause. Since the cause is wholesome, in principle it must have a pleasant fruit, so he uses the cause as proof. Baoliang says: In the third objection, because the wholesome is the cause of pleasure, one knows there cannot be an absence of pleasure.