Srimad-Bhagavatam: Canto 6 - Chapter 1 - Verse 20
Sanskrit:
श्रीराजोवाचकथं त आसुरं भावमपोह्यौत्पत्तिकं गुरो ।इन्द्रेण प्रापिता: सात्म्यं किं तत्साधु कृतं हि तै: ॥ २० ॥
ITRANS:
śrī-rājovācakathaṁ ta āsuraṁ bhāvamapohyautpattikaṁ guroindreṇa prāpitāḥ sātmyaṁkiṁ tat sādhu kṛtaṁ hi taiḥ
Translation:
King Parīkṣit inquired: My dear lord, due to their birth, the forty-nine Maruts must have been obsessed with a demoniac mentality. Why did Indra, the King of heaven, convert them into demigods? Did they perform any rituals or pious activities?