Śrīmad-Bhāgavatam · Text 6.9.18
Who is speaking and story frame
येनावृता इमे लोकास्तपसा त्वाष्ट्रमूर्तिना ।
स वै वृत्र इति प्रोक्त: पाप: परमदारुण: ॥ १८ ॥
yenāvṛtā ime lokās
tapasā tvāṣṭra-mūrtinā
sa vai vṛtra iti proktaḥ
pāpaḥ parama-dāruṇaḥ
That very fearful demon, who was actually the son of Tvaṣṭā, covered all the planetary systems by dint of austerity. Therefore he was named Vṛtra, or one who covers everything.
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