Valmiki Ramayana Aranya Kanda Sarga 73 Shloka 33
Original Shlokaनत्वेनं विषमाचार पापकर्माऽधिरोहति।।3.73.33।। यस्तु तं विषमाचारः पापकर्माऽधिरोहति। तत्रैव प्रहऱन्त्येनं सुप्तमादाय राक्षसाः।।3.73.34।।
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विषमाचारः a place of uneven terrain for movement, पापकर्मा sinner, एवम् so also, न अधिरोहति cannot ascend, विषमाचारः evil doer, पापकर्मा sinner, यः whoever, तम् him, अधिरोहति ascends, सुप्तम् when asleep, तम् him, आदाय taking, राक्षसाः demons, तत्रैव there itself, प्रहरन्ति strike at him.
If an evildoer or a sinner ascends the (Rishyamuka) mountain, he, in his sleep, will be thrown down with asleep by the demons from there itself. A sinner does not climb this mountain of uneven terrain.