大般涅槃經疏 14.14

14.14

第二觀老、第三觀病，二文可解。然生定在死前，病不必在老後。今文先老後病者，少時病者猶有望差，老時若病催死則病如將崩更折，故在老後明病。文釋病苦而云身心安隱者，解有二：一云只安隱是病，如大庾小庾。父子分別十年後得相見，白日相慶，過夜即死，此安隱是病。

The second, contemplating old age, and the third, contemplating illness, can be understood from the two texts. However, birth definitely precedes death, whereas illness does not necessarily follow old age. That the present text puts old age first and illness later is because if one falls ill when young, there is still hope of recovery, but if one falls ill in old age, it precipitates death, and the illness is like collapsing further when already about to crumble; hence illness is explained after old age. The text explains the suffering of illness yet says "body and mind are at peace"; there are two explanations: one says that peace itself is illness, like large and small granaries. When father and son are separated for ten years and then manage to meet, rejoicing during the day and dying after nightfall, this peace is illness.