注維摩詰經 7.54

7.54

肇曰：現身涅槃而方入生死。自上所列於菩薩皆為非道，而處之無閡，乃所以為道，故曰通達佛道也。

[Seng]zhao says: They manifest a body in nirvāṇa while just then entering saṃsāra. All the things listed above are non-paths for a bodhisattva, yet dwelling in them without hindrance is precisely how they make them the path; thus it is called 'penetrating the Buddha path'.