Srimad-Bhagavatam: Canto 9 - Chapter 1 - Verse 11
Sanskrit:
दृष्ट्वाग्न्यागार आसीनमावेशितधियं मुनिम् ।भगवत्युत्तमश्लोके जघ्नुस्ते पापनिश्चया: ॥ ११ ॥
ITRANS:
dṛṣṭvāgny-āgāra āsīnamāveśita-dhiyaṁ munimbhagavaty uttamaślokejaghnus te pāpa-niścayāḥ
Translation:
The sons of Kārtavīryārjuna were determined to commit sinful deeds. Therefore when they saw Jamadagni sitting by the side of the fire to perform yajña and meditating upon the Supreme Personality of Godhead, who is praised by the best of selected prayers, they took the opportunity to kill him.