Srimad-Bhagavatam: Canto 12 - Chapter 1 - Verse 50
Sanskrit:
एवं ह्यनादिनिधनो भगवान् हरिरीश्वर: ।कल्पे कल्पे स्वमात्मानं व्यूह्य लोकानवत्यज: ॥ ५० ॥
ITRANS:
evaṁ hy anādi-nidhanobhagavān harir īśvaraḥkalpe kalpe svam ātmānaṁvyūhya lokān avaty ajaḥ
Translation:
For the protection of all the worlds, the Supreme Personality of Godhead Hari, who is unborn and without beginning or end, thus expands Himself during each day of Brahmā into these specific categories of His personal representations.