Chapter 9 · The Royal Secret · Krishna said
Bhagavad Gita 9.7 — The cosmic cycle
सर्वभूतानि कौन्तेय प्रकृतिं यान्ति मामिकाम्। कल्पक्षये पुनस्तानि कल्पादौ विसृजाम्यहम् ॥
sarvabhūtāni kaunteya prakṛtiṃ yānti māmikām | kalpakṣaye punastāni kalpādau visṛjāmyaham ||
Meaning
At the end of a cosmic age, Arjuna, all beings merge into my nature; at the start of the next age, I send them forth again.