The works of Ādi Śaṅkarācārya

Sanatsujātīyam

p. 178

p. 178

प्रमादं वै मृत्युमहं ब्रवीमि सदाप्रमादममृतत्वं ब्रवीमि ॥ ४ ॥

In plain words

Heedlessness — that, I say, is death. Vigilance that never lapses — that, I say, is deathlessness.

Close to the Sanskrit

Heedlessness indeed I call death; ever-vigilance I call immortality.