大乘百法明門論開宗義決 1.92

1.92

異熟若是善染等者。流轉即是生死因果。流謂集諦。轉謂苦諦。還滅即是涅槃因果。還謂道諦。滅謂滅諦。凡言異熟皆謂無記。隨善惡業任運相續。若是善者不隨染緣。流轉五趣應不得成。若唯染者不受善熏。還滅涅槃如何得立。

Regarding "if vipāka were wholesome or defiled, etc.": Cyclic transmigration (saṃsāra) is precisely the cause and effect of birth and death. "Transmigration" refers to the truth of origin (samudaya-satya); "cyclic" refers to the truth of suffering (duḥkha-satya). Returning to cessation (pravṛtti-nivṛtti) is precisely the cause and effect of nirvāṇa. "Returning" refers to the truth of the path (mārga-satya); "cessation" refers to the truth of cessation (nirodha-satya). In general, whenever vipāka is mentioned, it always refers to the indeterminate (avyākṛta), continuing spontaneously in accordance with wholesome and unwholesome karma. If it were wholesome, it would not follow defiled conditions, and transmigration through the five destinies could not be accomplished. If it were solely defiled, it would not receive wholesome perfuming, and how could returning to cessation in nirvāṇa be established?