Valmiki Ramayana Sundara Kanda Sarga 42 Shloka 35
Original Shlokaन रावणसहस्रं मे युद्धे प्रतिबलं भवेत्। शिलाभिस्तु प्रहरतः पादपैश्च सहस्रशः।।5.42.35।।
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सहस्रशः a thousand ways, शिलाभिः with stones, पादपैश्च with even trees, प्रहरतः while I pound, मे to me, युद्धे in war, रावणसहस्रम् a thousand Ravanas, प्रतिबलम् match in strength, न भवेत् will not.
Even a thousand Ravanas will not match me in strength when I pound stones and trees in a thousand ways.