Śrīmad-Bhāgavatam · Text 12.11.50
Who is speaking and story frame
एवं ह्यनादिनिधनो भगवान् हरिरीश्वर: ।
कल्पे कल्पे स्वमात्मानं व्यूह्य लोकानवत्यज: ॥ ५० ॥
evaṁ hy anādi-nidhano
bhagavān harir īśvaraḥ
kalpe kalpe svam ātmānaṁ
vyūhya lokān avaty ajaḥ
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.
Read the purport on Vedabase.ioFrom Canto 10, chapter 14 onward, the translation and purports were completed by Śrīla Prabhupāda's disciples after his departure, and published by the Bhaktivedanta Book Trust.