nivṛtteṣu - when they were completed; aśva-medheṣu - his performances of the horse sacrifice; rājā - the King (Yudhiṣṭhira); yuṣmat - your (Parīkṣit's); pitāmahāḥ - grandfather; śṛṇvan - while hearing; bhagavataḥ - from the Supreme Lord (Kṛṣṇa); dharmān - religious principles; apṛcchat - he asked; idam - this; acyutam - of Lord Kṛṣṇa.

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.