Valmiki Ramayana Sundara Kanda Sarga 37 Shloka 43
Original Shlokaअयुक्तं तु कपिश्रेष्ठ मम गन्तुं त्वयाऽनघ। वायुवेगसवेगस्य वेगो मां मोहयेत्तव।।5.37.43।।
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अनघ sinless one, कपिश्रेष्ठ foremost monkey, त्वया by you, मम my, गन्तुम् to go with, अयुक्तम् not proper, वायुवेगसवेगस्य of a person with the speed of the wind, तव your, वेगः speed, माम् me, मोहयेत् will render me unconscious.
"O sinless and foremost monkey going with you is not proper for me. Your windlike speed will render me unconscious.