Srimad-Bhagavatam: Canto 11 - Chapter 1 - Verse 20
Sanskrit:
दृष्ट्वा मां त उपव्रज्य कृत्वा पादाभिवन्दनम् ।ब्रह्माणमग्रत: कृत्वा पप्रच्छु: को भवानिति ॥ २० ॥
ITRANS:
dṛṣṭvā māṁ ta upavrajyakṛtvā pādābhivandanambrahmāṇam agrataḥ kṛtvāpapracchuḥ ko bhavān iti
Translation:
Thus seeing Me, the sages, placing Brahmā in the lead, came forward and worshiped My lotus feet. Then they frankly asked Me, “Who are You?”
Purport:
Śrīla Bhaktisiddhānta Sarasvatī Ṭhākura comments, “When Brahmā was unable to answer the question placed by the sages, he fixed his mind in thought of the Supreme Lord. The Lord then assumed the form of Haṁsa and appeared before Lord Brahmā and the sages, who proceeded to inquire about the specific identity of the Lord.”