Ramayana
नह्येष हन्तुं शक्यो ऽद्य वरदानात्सुनिर्भयः । तद्ग्रहीष्यामहे रक्षो यत्ता भवत संयुगे ॥ 7-29-15 ॥
He cannot be slain today, for by the boon granted to him he is wholly free from fear; therefore we shall seize this Rakshasa instead. Be ready, then, for the battle.
english translation