āvṛitaṁ jñānam etena jñānino nitya-vairiṇā
kāma-rūpeṇa kaunteya duṣhpūreṇānalena cha || 39||

My Understanding : Lust clouds your intelligence and becomes your greatest enemy. It draws you toward many things, leading you to commit sinful acts. Desires and attachments make you fall prey to your own inner enemy. Therefore, it is essential to always control yourself.