Srimad-Bhagavatam: Canto 10 - Chapter 1 - Verse 6
Sanskrit:
निवृत्तेष्वश्वमेधेषु राजा युष्मत्पितामह: ।शृण्वन् भगवतो धर्मानपृच्छदिदमच्युतम् ॥ ६ ॥
ITRANS:
nivṛtteṣv aśva-medheṣurājā yuṣmat-pitāmahaḥśṛṇvan bhagavato dharmānapṛcchad idam acyutam
Translation:
Your grandfather, King Yudhiṣṭhira, after completing his Aśvamedha sacrifices, asked Lord Acyuta this very same question while hearing the Lord’s explanation of religious principles.