Chapter 3 · The Yoga of Action · Krishna said
Bhagavad Gita 3.39 — An unquenchable fire
आवृतं ज्ञानमेतेन ज्ञानिनो नित्यवैरिणा। कामरूपेण कौन्तेय दुष्पूरेणानलेन च ॥
āvṛtaṃ jñānametena jñānino nityavairiṇā | kāmarūpeṇa kaunteya duṣpūreṇānalena ca ||
Meaning
Knowledge is covered by this constant enemy of the wise, desire, which is like a fire that can never be satisfied, Arjuna.