Prabhupada's lecture - Śrīmad-Bhāgavatam 1.5.23 - Vṛndāvana, August 4, 1974
So here, how he became Nārada Muni will be described. But here it is said... One thing is that when you are liberated... Just like in the Bhagavad-gītā it is said that tyaktvā dehaṁ punar janma naiti mām eti [Bg. 4.9]. You become an associate of Nārāyaṇa, Kṛṣṇa, Viṣṇu. Then you can remember your past lives. Remember your past lives. Just like you can remember your dreams, "I was dreaming like that." So this is all dream. Our, this life, at the present moment, because this body is false, so whatever we are acting, it is just like dream. Just like in dream at night we also work. So this is gross dream and that is subtle dream. But real life is spiritual life. But we foolish people, we are taking this life as permanent life, permanent settlement. It is not permanent settlement. Here is..., Nārada Muni's saying, ahaṁ purā atīta-bhave abhavam. Atīta-bhave. This nature... Just like everything material... Bhūtvā bhūtvā pralīyate [Bg. 8.19]. It appears for some time like bubbles in the ocean, few seconds. Again finished. The whole cosmic manifestation in which we are millions and millions of years, it is just like a bubble in the ocean. It is just like a bubble. Bhūtvā bhūtvā pralīyate [Bg. 8.19]. It is said in the Bhagavad-gītā.
So Nārada Muni confirms that "Formerly, in the millennium..." That is Brahmā's night. When Brahmā's night comes, everything becomes devastated in water. Sahasra-yuga-paryantam ahar yad brahmaṇo viduḥ [Bg. 8.17]. First of all sahasra-yuga. One yuga means forty-three hundred thousands of years. Multiply it by one thousand. That is the period of manifestation.