Valmiki Ramayana Yuddha Kanda Sarga 60 Shloka 12
Original Shlokaएतदेवाभ्युपागम्ययत्नंकर्तुमहार्हथ ।।6.60.12।। राक्षसाश्चापितिष्ठन्तुचर्यागोपुरमूर्थसु ।
1 source checked for this shloka
एतत् एव all this, अभ्युपागम्य knowing, इह here, यत्नम् make effort, कर्तुम् will do, अर्हथ ought to, राक्षसाश्चापि even Rakshasas, चर्यागोपुरमूर्धसु strive to succeed positioned at the top of gates, तिष्ठन्तु positioned.
"Knowing all this, make effort doing what ought to be done and let the Rakshasas strive to succeed positioned on top of the gates."