Valmiki Ramayana Bala Kanda Sarga 40 Shloka 29
Original Shlokaश्रुत्वा तु वचनं तेषां कपिलो रघुनन्दन। रोषेण महताऽऽविष्टो हुङ्कारमकरोत्तदा।।1.40.29।।
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रघुनन्दन O Rama, कपिल: Kapila, तेषाम् their, वचनम् words, श्रुत्वा having heard, तदा then, महता great, रोषेण wrath, आविष्ट: overwhelmed, हुङ्कारम् the sound "H'm", अकरोत् uttered.
"O descendant of Raghu Kapila, having heard their words, overwhelmed with great wrath, uttered the sound "H'm".