Valmiki Ramayana Sundara Kanda Sarga 43 Shloka 9
Original Shlokaदासोऽहं कोसलेन्द्रस्य रामस्याक्लिष्टकर्मणः। हनुमान्शत्रुसैन्यानां निहन्ता मारुतात्मजः।।5.43.9।।
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शत्रुसैन्यानाम् of enemy army, निहन्ता killer, मारुतात्मजः son of the Windgod, हनुमान् Hanuman, अहम् I, कोसलेन्द्रस्य king of Kosala's, अक्लिष्टकर्मणः one who can acomplish any task with ease, रामस्य Rama's, दासः servant.
'I am the son of the Windgod, destroyer of enemy army. I am a servant of Rama, the king of Kosala who can accomplish any task with ease.