B.G 8.17, 18, 19 and 20
sahasrayugaparyantamaharyadbrahmaṇo viduḥ। rātriṁ yugasahasrāntāṁ te'horātravido janāḥ ॥17॥
Those who know the nature of day and night understand that the day of Brahmā lasts for a thousand yugas, and his night also ends after a thousand yugas.
avyaktād vyaktayaḥ sarvāḥ prabhavantyaharāgame। rātryāgame pralīyante tatraivāvyaktasañjñake ॥18॥
From the unmanifest, all manifest beings arise at the beginning of the day (of Brahmā), and at the arrival of the night, they dissolve back into that which is called the unmanifest.
bhūtagrāmaḥ sa evāyaṁ bhūtvā bhūtvā pralīyate। rātryāgame'vaśaḥ pārtha prabhavatyaharāgame ॥19॥
O Pārtha (Arjuna), this multitude of beings, being born again and again, dissolves at the arrival of the night (of Brahmā) helplessly, and at the arrival of the day, it comes into existence again.
parastasmāttu bhāvo'nyovyakto vyaktāt sanātanaḥ। yaḥ sa sarveṣu bhūteṣu naśyatsu na vinaśyati ॥20॥
But beyond that unmanifest (existence), there is another eternal unmanifest reality, which does not perish even when all beings perish.
Gīta Tātparya 8.17, 18, 19 and 20
The Supreme Brahman is not destroyed when the dissolution of all manifested beings occurs. 'sahasra' - many or infinite. 'brahmaṇa' - the Supreme Brahman.
sahasramiti bahveva। brahmaṇaḥ parabrahmaṇaḥ।
"Sahasram" (a thousand) signifies multitude or infinite. It word 'brahmaṇa' refers to the Supreme Brahman.
"avyaktād vyaktayaḥ sarvāḥ prabhavantyaharāgame। rātryāgame pralīyante tatraivāvyaktasañjñake॥"
"All manifest beings arise from the unmanifest at the arrival of the day. At the arrival of the night, they dissolve into that very unmanifest, which is so designated."
iti vākyaśeṣāt।
- stated thus in the remainder of the statement.
na hi viriñcāhanyeva sarvavyaktalayaḥ।
Indeed, the Brahman is not destroyed when the dissolution of all manifested beings occurs.
"nityasyāpi hareḥ kālo dviparārdhātmakastvayam। ahaḥścāsau nimeṣaścetyapravr̥ttyopacaryate॥"
"Even though Lord Hari is eternal, His time is considered in terms of two parārddhas each for a day and night. It is indeed a mere blink of an eye for the inactive One."
iti ca ॥17॥
- stated thus as well.
