avrtam jnanam etena
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Thus the wise living entity’s pure consciousness becomes covered by his eternal enemy in the form of lust, which is never satisﬁed and which burns like ﬁre.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
It is said in the Manu-smrti that lust cannot be satisﬁed by any amount of sense enjoyment, just as ﬁre is never extinguished by a constant supply of fuel. In the material world, the center of all activities is sex, and thus this material world is called maithunya-agara, or the shackles of sex life. In the ordinary prison house, criminals are kept within bars; similarly, the criminals who are disobedient to the laws of the Lord are shackled by sex life. Advancement of material civilization on the basis of sense gratiﬁcation means increasing the duration of the material existence of a living entity. Therefore, this lust is the symbol of ignorance by which the living entity is kept within the material world. While one enjoys sense gratiﬁcation, it may be that there is some feeling of happiness, but actually that so-called feeling of happiness is the ultimate enemy of the sense enjoyer.
[To hear on this verse, visit – http://bhagavadgitaclass.com/bhagavad-gita-chapter-03-text-39/]