Valmiki Ramayana Sundara Kanda Sarga 36 Shloka 40
Original Shlokaक्षिप्रं द्रक्ष्यसि वैदेहि रामं प्रस्रवणे गिरौ। शतक्रतुमिवासीनं नागराजस्य मूर्धनि।।5.36.40।।
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वैदेहि Vaidehi, प्रस्रवणे गिरौ on mount Prasravana, रामम् Rama, नागराजस्य elephant's, मूर्धनि on the back, आसीनम् seated, शतक्रतुम् इव like Indra who has performed a hundred sacrifices, क्षिप्रम् soon, द्रक्ष्यसि you will see.
"O Vaidehi, you will soon see Rama seated on the Prasravana mountain just as Indra (who performed a hundred sacrifices) seated on the back of the king of elephants.