摩訶止觀 3.159

3.159

束此十二，是無漏界中四種障，謂：緣、相、生、壞。緣即煩惱道；相即業道；生、壞即苦道。故知界外有十二因緣。所以者何？降佛已下，皆有無明；無明潤業；業既被潤，那得無苦？此十二輪雖不退界墮下，不妨從無明輪至老死，從老死輪至無明。障於實理，良由此惑。此惑為「入假」、「入中」兩觀所治。

Condensing these twelve, they are the four kinds of obstacles within the untainted realm, namely: condition, mark, arising, and destruction. Condition is the path of affliction; mark is the path of karma; arising and destruction are the path of suffering. Hence we know that beyond the realm there are the twelve links of dependent origination. Why is this? Below the Buddha, all possess avidyā; avidyā moistens karma; once karma has been moistened, how could there not be suffering? Although these twelve links of the wheel do not regress to lower realms, this does not prevent revolving from the wheel of avidyā to old age and death, and from old age and death to avidyā. Obstructing the real principle is truly due to this delusion. This delusion is cured by the two contemplations of "entering the provisional" and "entering the middle."