Valmiki Ramayana Aranya Kanda Sarga 39 Shloka 21
Original Shlokaसोऽऽहं तवापराधेन विनश्येयं निशाचर। कुरु यत्ते क्षमं तत्त्वमहं त्वा नानुयामि ह।।3.39.21।।
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निशाचर O demon, सः अहम् that I, तव अपराधेन by your mistake, विनश्येयम् I will be ruined, ते to you, यत् whatever, क्षमम् appropriate, तत् that, त्वम् you, कुरु you may do, अहम् I, त्वा you, न अनुयामि ह will not follow.
O demon As such, I will perish due to your offence. You may do anything you deem appropriate. I will not follow you.