淨名經集解關中疏 1.289

1.289

是身無定為要當死　死苦肇曰。壽夭雖無定不得不受死。此必死想也。

"This body has no stability; it must inevitably die." This is the suffering of death. Sengzhao states: "Although lifespan and early death are not fixed, one cannot avoid suffering death; this is the perception of inevitable death."