Bhagavad Gita 8.18

अव्यक्ताद्वयक्तय: सर्वा: प्रभवन्त्यह्राग्मे |
रात्रिगमे प्रलीयन्ते तत्रैवव्यक्तसंज्ञके

Translation

At the advent of Brahma’s day, all living beings emanate from the unmanifest source. And at the fall of his night, all embodied beings again merge into their unmanifest source.