Bhagavad Gita
3.39

आवृतं ज्ञानमेतेन ज्ञानिनो नित्यवैरिणा | कामरूपेण कौन्तेय दुष्पूरेणानलेन च ||३९||

āvṛtaṁ jñānam etena jñānino nitya-vairiṇā kāma-rūpeṇa kaunteya duṣhpūreṇānalena cha

Translation

Thus the wise living entity's pure consciousness is covered by his eternal enemy in the form of lust, which is never satisfied and which burns like fire.

Interpretation

Desire is 'dushpurena analena' — the insatiable fire. No amount of satisfaction quenches it permanently; it returns again and again. This is its most insidious quality: it can never be fully satisfied through fulfillment. The only genuine resolution is transcendence — the discovery of the Self's own completeness that needs no external addition.