Valmiki Ramayana Yuddha Kanda Sarga 59 Shloka 119
Original Shlokaवायुसूनोःसुहृत्त्वेनभक्त्यापरमयाचसः ।।6.59.119।। शत्रूणामप्रकम्प्योऽपिलघुत्वमगमत्कपेः ।
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सः he, शत्रूणाम् for the enemies, अप्रकम्पःअपि unshakeable by enemies, वायुसूनोः son of wind god, सुहृत्त्वेन friend, परमया highly, भक्त्याच being devoted, कपेः monkey, लघुत्वम् became light, आगमत् became.
Lakshmana though unshakeable for enemies, became light for the son of wind god by his friendship and high devotion.