Valmiki Ramayana Ayodhya Kanda Sarga 78 Shloka 3
Original Shlokaबलवान्वीर्यसम्पन्नो लक्ष्मणो नाम योऽप्यसौ। किं न मोचयते रामं कृत्वा स्म पितृनिग्रहम्।।2.78.3।।
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बलवान् strong, वीर्यसम्पन्नः endowed with prowess, लक्ष्मणो नाम Lakshmana by name, यः whoever, असौ अपि even himself, पितृनिग्रहम् restraint of father, कृत्वा having made, रामम् Rama, किम् why, न मोचयते स्म did not release?.
And why did not Lakshmana who is strong and powerful release Rama from exile by restraining our father?