Valmiki Ramayana Yuddha Kanda Sarga 29 Shloka 28
Original Shlokaमोचितस्सोऽपिरामेणवध्यमानःप्लवङ्गमैः । अनृशंस्येनरामेणमोचिताराक्षसाःपरे ।।6.29.28।।
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प्लवङ्गमै monkeys, वध्यमान to kill, सोऽपि he too, रामेण by Rama, मोचित relieved, परे other, राक्षसा Rakshasas, अनृशंस्येन compassionate, रामेण by Rama, मोचिता got released.
As the monkeys attempted to kill him (Saardula), compassionate Rama released him and also the other Rakshasas.