By this, the constant enemy, knowledge is covered, the knowledge of the knower. For the knower knows beforehand 'by this I am being set to harm', and he is constantly miserable; so this is the constant enemy of the knower, not of the fool. For the fool, while the craving lasts, sees desire as a friend, and only when the pain that is its fruit comes does he know 'I have been brought to misery by craving', not beforehand. So it is the constant enemy of the knower alone. In what form? In the form of desire: longing itself is its form; and by that desire, which is hard to fill, since its filling is achieved only with difficulty, and which is therefore an unsatisfied fire, since for it there is no sufficiency, no enough. Where does this desire have its seat, that, by being a coverer of knowledge, it is the enemy of all the world? When the enemy's seat is known, it can be struck down with ease. To this He says.

The knowledge directed at the self, belonging to this creature, the knower, whose very nature is knowledge, is veiled by this working of desire, the eternal foe that breeds the bewilderment of objects, and by this fire, hard to fill, never satisfied, since its object, the objects of sense, can never be filled. By what instruments does this desire establish itself over the self? To this the Lord speaks.

Knowledge, even when it has arisen from scripture, does not, when veiled by desire, shine forth so as to give the direct vision of the supreme Self; this holds of the man of knowledge, much more of one of slight knowledge. 'By desire' means by the eternal foe named desire, hard to fill, for desire is filled only with pain. The station of Indra and the rest is not won with ease, and even when the station of Indra and the rest is reached one desires further the station of Brahma and the rest, so that there is never the thought 'enough'; hence it is called a fire that has no 'enough'. And it is said, 'for knowledge, which is of Brahman, desire is the smoke that is to fire; for the buddhi it is the dirt that is to the mirror; and for the living being it is the caul that is to the embryo'.