妙法蓮華經玄義 10.173

10.173

又涅槃即生死，苦諦清淨也；菩提即煩惱，集諦清淨也；煩惱即菩提，道諦清淨也；生死即涅槃，滅諦清淨也。此圓教中四修多羅。

Furthermore, nirvāṇa is saṃsāra, which is the purity of the truth of suffering; bodhi is affliction, which is the purity of the truth of suffering's origin; affliction is bodhi, which is the purity of the truth of the path; saṃsāra is nirvāṇa, which is the purity of the truth of cessation. These are the four sūtras within the perfect teaching.