jnyaanena tu tadajnyaanam yeshaam naashitamaatmanaha |
teshaamaadityavatjnyaanam prakashayati tatparam || 16 ||

For those who have destroyed ignorance through knowledge, such knowledge illumines the eternal essence, just like the sun.

jnyaanena : through knowledge
tu : for
tat : that
ajnyaanam : ignorance
yeshaam : those who have
naashitam : destroyed
aatmanaha : their
teshaam : for them
aadityavat : like the sun
jnyaanam : knowledge
prakashayati : illumines
tat : that
param : eternal essence

In this shloka, Shri Krishna compares the dispelling of ignorance to the dispelling of darkness by the sun. The light of the sun does not create anything new. It just shows us what was already there, but was hidden by darkness. Similarly, the knowledge of the eternal essence does not create anything new in us. It just reveals our true nature.

Why does Shri Krishna emphasize knowledge so much? The central theme of the Gita is the removal of delusion. The root cause of delusion is ignorance, which is nothing but our identification to the body, mind and intellect. All our efforts should be towards uprooting this ignorance through the correct knowledge. However, our lives are spent in trying to solve problems at the worldly level.

There is always one aspect of our lives that is incomplete or imperfect. For some of us, it could be our job. For others, it could be our family and friends. For some others, it could be our health. Given these various imperfections, we try to better our situation by changing our job, friends and so on. This results in a roller coaster ride of joys and sorrows.

But if we take a truly objective look at this situation, it turns out that we are looking for perfection in the material world, which will always be imperfect. Shri Krishna says here that the only way to get to the root of this problem is to remove our ignorance of the eternal essence.