摩訶止觀 7.97

7.97

又復當觀：過去無明、善惡諸業，驅縛心識，偪入胎獄。如繫鳥在籠欲去不得。心識亦爾，籠以四大，繫以得繩；心在色籠無處不至。業繩未斷，去已復還；籠破繫斷，即去不反，空籠而存。此壞彼成，出籠入籠，印壞文成，無一念住。又風氣依身，名「出入息」；此息遷謝，出不保入。《毘曇》云：「命是非色，非心法。」《大集》云：「出入息名『壽命』。」一息不返即名「命終」。比丘白佛：「不保七日，乃至不保出入息。」佛言：「善哉，善修無常。」

Furthermore, one should contemplate: past ignorance and all karmas, both good and evil, drive and bind mental consciousness, forcing it into the prison of the womb. It is like a tied bird in a cage wanting to leave but unable. Mental consciousness is also like this: caged by the four elements, bound by the cord of attainment; the mind is inside the cage of form, yet there is nowhere it does not reach. When the cord of karma is not severed, after departing it returns again; when the cage breaks and the binding is severed, it departs and does not return, leaving an empty cage behind. As this disintegrates, that is formed; leaving the cage and entering the cage, as the seal is destroyed the imprint is formed, without staying for a single thought-moment. Moreover, the wind-breath relies on the body, which is called 'inhalation and exhalation'; this breath changes and passes away, and as it goes out there is no guarantee it will come in. The Abhidharma says: 'Life is neither form nor mind.' The Mahāsaṃnipāta says: 'Inhalation and exhalation are called "lifespan".' When a single breath does not return, it is called 'the end of life.' A monk said to the Buddha: 'I do not guarantee seven days, even up to not guaranteeing the in-and-out breath.' The Buddha said: 'Excellent! You cultivate impermanence well.'