Srimad-Bhagavatam: Canto 8 - Chapter 1 - Verse 38
Sanskrit:
मयास्मै यद् वरो दत्तो मृत्युर्नैवार्द्रशुष्कयो: ।अतोऽन्यश्चिन्तनीयस्ते उपायो मघवन् रिपो: ॥ ३८ ॥
ITRANS:
mayāsmai yad varo dattomṛtyur naivārdra-śuṣkayoḥato ’nyaś cintanīyas teupāyo maghavan ripoḥ
Translation:
The voice also said, “O Indra, because I have given this demon the benediction that he will never be killed by any weapon that is dry or moist, you have to think of another way to kill him.”