大方廣佛華嚴經隨疏演義鈔 29.27

29.27

疏「無為無因而體是果」者，即《涅槃．師子吼品》云「涅槃無因而體是果。若涅槃有因，不得名為般涅槃也。」謂涅槃之體畢竟無因，如無我我所故。亦如《俱舍》無為無因果，謂六因無五，但有能作，故名捨因而體是果。則離繫果菩提之道，望此亦因者，要得菩提證涅槃故。此菩提亦名為因，是果中因故。滅理涅槃亦是因家之果，又是菩提果家之果故。

Regarding the commentary's "the unconditioned has no cause, yet its essence is a fruit": fascicle [twenty-seven, the] "Lion's Roar Chapter" of the Nirvāṇa [Sūtra] says, "Nirvāṇa has no cause, yet its essence is a fruit. If nirvāṇa had a cause, it could not be called parinirvāṇa." This means that the essence of nirvāṇa is ultimately without cause, just as it is devoid of self and what belongs to self. It is also like the Kośa's statement that the unconditioned has no causes and no fruits; meaning that of the six causes it lacks five, having only the efficient cause, and hence it is said to cast off causes, yet its essence is a fruit. Then the fruit of detachment, the path of bodhi, with respect to this is also a cause, because one must attain bodhi to realize nirvāṇa. This bodhi is also named a cause, being a cause within fruit; the principle of cessation, nirvāṇa, is also the fruit of the cause, and moreover the fruit of the fruit that is bodhi.