Verse
आवृतं ज्ञानमेतेन ज्ञानिनो नित्यवैरिणा ।कामरूपेण कौन्तेय दुष्पूरेणानलेन च ॥
āvṛtaṃ jñānametena jñānino nityavairiṇākāmarūpeṇa kaunteya duṣpūreṇānalena ca
Enveloped is knowledge, O Kaunteya, by this eternal enemy of knowledge in the form of desire which is an insatiable fire.
Gītā 3·39