Shiva Purana

siva.sh/siva-purana/rudra-samhita/2/6

इत्थं तपति तस्मिन्वै नारदे मुनिसत्तमे ।। चकंपेऽथ शुनासीरो मनस्संतापविह्वलः ।। ६ ।।

sanskrit

When the great sage Nārada was thus performing penance, the mind of Indra became excessively agitated and he trembled.

english translation

itthaM tapati tasminvai nArade munisattame || cakaMpe'tha zunAsIro manassaMtApavihvalaH || 6 ||

hk transliteration by Sanscript