Srimad-Bhagavatam: Canto 6 - Chapter 1 - Verse 15
Sanskrit:
वृत्रमभ्यद्रवच्छत्रुमसुरानीकयूथपै: ।पर्यस्तमोजसाराजन् क्रुद्धो रुद्र इवान्तकम् ॥ १५ ॥
ITRANS:
vṛtram abhyadravac chatrumasurānīka-yūthapaiḥparyastam ojasā rājankruddho rudra ivāntakam
Translation:
My dear King Parīkṣit, as Rudra, being very angry at Antaka [Yamarāja] had formerly run toward Antaka to kill him, Indra angrily and with great force attacked Vṛtrāsura, who was surrounded by the leaders of the demoniac armies.