注維摩詰經 7.166

7.166

什曰：諸天以種種名藥著海中，以寶山摩之令成甘露，食之得仙，名不死藥。佛法中以涅槃甘露令生死永斷，是真不死藥也。亦云劫初地味甘露，食之則長生。佛法中則實相甘露養其慧命，是真甘露食也。生曰：天食為甘露味也，食之長壽，遂號為不死食也。泥洹是不死之法，故以諭焉。

[Kumāra]jīva says: The devas put various famous medicines into the ocean and grind them with precious mountains to produce amṛta; eating it, they become immortals, and it is called the medicine of immortality. In the Buddha-Dharma, using the amṛta of nirvāṇa, saṃsāra is permanently severed; this is the true medicine of immortality. It is also said that at the beginning of the kalpa there was the taste of the earth, amṛta, eating which gave long life. In the Buddha-Dharma, the amṛta of the true mark nourishes one's wisdom-life; this is the true food of amṛta.
[Dao]sheng says: The food of devas has the flavor of amṛta; eating it brings longevity, hence it is named the food of immortality. Nirvāṇa is the dharma of immortality, therefore it is used as a metaphor.