Valmiki Ramayana Yuddha Kanda Sarga 18 Shloka 37
Original Shlokaतस्मात् क्षिप्रंसहास्माभिस्तुल्योभवतराघव: । विभीषणोमहाप्राज्ञस्सखित्वंचाभ्युपैतुनः ।।6.18.37।।
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राघव: Rama, तस्मात् therefore, महाप्राज्ञः highly sagacious one, विभीषणः Vibheeshana, क्षिप्रम् at once, अस्माभिस्सह: along with us, तुल्यः equal term, भवतु: be, नः our, सखित्वंच: friendship, अभ्युपैतु: you enjoy.
"Rama therefore, let this highly sagacious Vibheeshana be with you like a friend in equal terms and enjoy."