Srimad-Bhagavatam: Canto 3 - Chapter 1 - Verse 3
Sanskrit:
तस्य चोद्धरत: क्षौणीं स्वदंष्ट्राग्रेण लीलया ।दैत्यराजस्य च ब्रह्मन् कस्माद्धेतोरभून्मृध: ॥ ३ ॥
ITRANS:
tasya coddharataḥ kṣauṇīṁsva-daṁṣṭrāgreṇa līlayādaitya-rājasya ca brahmankasmād dhetor abhūn mṛdhaḥ
Translation:
What was the reason, O brāhmaṇa, for the fight between the demon king and Lord Boar while the Lord was lifting the earth as His pastime?