Valmiki Ramayana Kishkindha Kanda Sarga 3 Shloka 38
Original Shlokaयथा ब्रवीषि हनुमान्सुग्रीववचनादिह। तत्तथा हि करिष्यावो वचनात्तव सत्तम4.3.38।।
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सत्तम O virtuous one, हनुमन् Hanuman, इह here, सुग्रीववचनात् by Sugriva's words, यथा those, ब्रवीषि you speak, तत् that, तव your, वचनात् words, तथा so also, करिष्यावः we will do
'O virtuous Hanuman we will do whatever you are saying, for it is the message of Sugriva.