大般涅槃經義記 10.149

10.149

苦中，初先結前生後、次辨、後結。辨中有四：一總觀苦因於無常、二觀無常故受生老病死之苦、三觀無常故受於苦苦、四觀無常故生五盛陰。

Regarding suffering, first he connects the preceding and introduces what follows, next explains, and finally concludes. In the explanation there are four: first, generally contemplating that suffering is caused by impermanence; second, contemplating that due to impermanence one undergoes the suffering of birth, old age, sickness, and death; third, contemplating that due to impermanence one undergoes the suffering of suffering; fourth, contemplating that due to impermanence there arise the five aggregates of grasping.