Valmiki Ramayana Ayodhya Kanda Sarga 102 Shloka 33
Original Shlokaतेषां तु रुदतां शब्दात् प्रतिशब्दोऽभवद् गिरौ। भ्रातॄणां सह वैदेह्या सिंहानां नर्दतामिव।।2.102.33।।
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वैदेह्या सह with Sita, रुदताम् of those lamenting people, तेषां भ्रात्रूणाम् all the brothers', शब्दात् with the sound, नर्दताम् roaring, सिंहानामिव like the lions, शब्दात् with sound, गिरौ in the mountain, प्रतिशब्दः अभवत् was echoed.
The mountain echoed with the sound of lamentations of all the brothers along with Sita which resembled the roar of lions.