Valmiki Ramayana Yuddha Kanda Sarga 118 Shloka 14
Original Shlokaनिर्जिताजीवलोकस्यतपसाभावितात्मना । अगस्त्येनदुराधर्षामुनिनादक्षिणेवधिक् ।।6.118.14।।
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तपसा by austerity, भावितात्मना realized master, अगस्त्येन by Agastya, जीवलोकस्य world of mortals, दुराधर्षा difficult to assail, दक्षिणाधिक् इव southern quarter, निर्जिता killing
"Though the southern quarter is difficult to assail for the world of mortals, Agastya, a realized sage, has won by the power of his austerity. In the same way I have won you."