Śrīmad-Bhāgavatam · Text 11.13.19
Who is speaking and story frame
स मामचिन्तयद् देव: प्रश्नपारतितीर्षया ।
तस्याहं हंसरूपेण सकाशमगमं तदा ॥ १९ ॥
sa mām acintayad devaḥ
praśna-pāra-titīrṣayā
tasyāhaṁ haṁsa-rūpeṇa
sakāśam agamaṁ tadā
Lord Brahmā desired to attain the answer to the question that was puzzling him, and thus he fixed his mind on Me, the Supreme Lord. At that time, in My form of Haṁsa, I became visible to Lord Brahmā.
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.