Bhagavad Gita, Chapter 2, Verse 69

या निशा सर्वभूतानां तस्यां जागर्ति संयमी । यस्यां जाग्रति भूतानि सा निशा पश्यतो मुनेः

yā niśā sarvabhūtānāṃ tasyāṃ jāgarti saṃyamī | yasyāṃ jāgrati bhūtāni sā niśā paśyato muneḥ

Translation

What is night to all beings, therein the self-controlled one is awake. Where all beings are awake, that is the night of the sage who sees.

— Alladi Mahadeva Sastri

Word meanings

yā

which

niśā

night

sarvabhūtānām

(of) all, of beings

tasyām

in that

jāgarti

wakes

saṃyamī

the disciplined (one)

yasyām

in (which)

jāgrati

wake

bhūtāni

creatures

sā

that

niśā

night

paśyataḥ

(of the) seeing

muneḥ

of the muni

Śaṅkarācārya's commentary

The Self, the supreme Reality, is the object of the self-controlled one's vigilance; and to ordinary beings, ignorant of the Self, that Reality is as night, for they do not perceive it. Conversely, the world of sense-objects in which ordinary beings live awake — pursuing them as real — is night for the seer who has known the Self, since to him they are as good as non-existent. The verse states that the orientation of the sage and that of the worldling are exactly inverted: each is awake where the other sleeps.