Ramayana
तन्न खल्वेष ते सौम्य पात्यो रावणमूर्धनि । नह्यस्मिन्पतिते कश्चिन्मुहूर्तमपि जीवति ॥ 7-22-44 ॥
"Therefore, gentle one, this rod must surely not be brought down by you upon Ravana's head; for once it falls upon him, no one lives even for a moment."
english translation