Srimad-Bhagavatam: Canto 1 - Chapter 1 - Verse 1
शौनक उवाचनिर्गते नारदे सूत भगवान् बादरायण: ।श्रुतवांस्तदभिप्रेतं तत: किमकरोद्विभु: ॥ १ ॥
śaunaka uvācanirgate nārade sūtabhagavān bādarāyaṇaḥśrutavāṁs tad-abhipretaṁtataḥ kim akarod vibhuḥ
Ṛṣi Śaunaka asked: O Sūta, the great and transcendentally powerful Vyāsadeva heard everything from Śrī Nārada Muni. So after Nārada’s departure, what did Vyāsadeva do?
In this chapter the clue for describing Śrīmad-Bhāgavatam is picked up as Mahārāja Parīkṣit is miraculously saved in the womb of his mother. This was caused by Drauṇi (Aśvatthāmā), Ācārya Droṇa’s son, who killed the five sons of Draupadī while they were asleep, for which he was punished by Arjuna. Before commencing the great epic Śrīmad-Bhāgavatam, Śrī Vyāsadeva realized the whole truth by trance in devotion.