SB 3.8.3

āsīnam urvyāṁ bhagavantam ādyaṁ
 saṅkarṣaṇaṁ devam akuṇṭha-sattvam
vivitsavas tattvam ataḥ parasya
 kumāra-mukhyā munayo ’nvapṛcchan
āsīnam — seated; urvyām — in the bottom of the universe; bhagavantam — unto the Lord; ādyam — the original; saṅkarṣaṇam — Saṅkarṣaṇa; devam — the Personality of Godhead; akuṇṭha-sattvam — undeterred knowledge; vivitsavaḥ — being inquisitive to know; tattvam ataḥ — truth like this; parasya — regarding the Supreme Personality of Godhead; kumāra — the boy-saint; mukhyāḥ — headed by; munayaḥ — great sages; anvapṛcchan — inquired like this.
Some time ago, being inquisitive to know, Sanat-kumāra, the chief of the boy-saints, accompanied by other great sages, inquired exactly like you about the truths regarding Vāsudeva, the Supreme, from Lord Saṅkarṣaṇa, who is seated at the bottom of the universe.

This is in clarification of the statement that the Lord spoke directly on the Śrīmad-Bhāgavatam. When and unto whom the Bhāgavatam was spoken is explained herewith. Questions similar to those put forward by Vidura were asked by great sages like Sanat-kumāra, and Lord Saṅkarṣaṇa, the plenary expansion of the Supreme Lord Vāsudeva, answered them.