維摩經玄疏 2.156

2.156

五、善知通塞者，知生死即涅槃、煩惱即菩提，則一切皆通；知涅槃即生死、菩提即煩惱，則一切皆塞也。

Fifth, skillfully knowing passage and blockage: knowing that saṃsāra is identical to nirvāṇa and defilements are identical to bodhi constitutes complete passage; knowing that nirvāṇa is identical to saṃsāra and bodhi is identical to defilements constitutes complete blockage.