釋氏要覽 3.359

3.359

西域傳云。祇桓西北角日光沒處。為無常院。若有病者當安其中意為凡人內心貪著房舍衣鉢道具生戀著心無厭背故制此堂令聞名見題悟一切法無彼常故（今稱延壽堂涅槃堂者皆後人隨情愛名之也）。

The Records of the Western Regions says: In the northwest corner of the Jetavana, where the sunlight sets, is the Hall of Impermanence. If there are sick persons, they should be placed in it. The intent is that ordinary people inwardly crave their rooms, robes, bowls, and implements, generating attachments without satiety or turning away; therefore this hall was established to make them, upon hearing its name and seeing its sign, awaken to the impermanence of all dharmas (Those now called "Hall of Prolonged Life" or "Nirvāṇa Hall" are all named by later people according to their emotional preferences).