Valmiki Ramayana Sundara Kanda Sarga 58 Shloka 144
Original Shlokaतेन वध्योऽहमाज्ञप्तो रक्षसा रौद्रकर्मणा। मत्प्रभावमविज्ञाय रावणेन दुरात्मना।।5.58.144।।
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रौद्रकर्मणा one who performs dreadful actions, रक्षसा by the demon, दुरात्मना evilminded one, तेन रावणेन by that Ravana, मत्प्रभावम् my power, अविज्ञाय not knowing, अहम् I, वध्यः to kill, आज्ञप्तः ordered.
"The evilminded demon, Ravana, who perpetrates dreadful acts ordered my slaughter, not knowing my power.