Summary of Bhagavad Gita Chapter 15

The fifteenth chapter of the Bhagavad Gita is unique in several respects. It is the shortest, with only twenty shlokas. On the other hand, it summarizes the entire essence of not just the Gita but also all the Vedas in those twenty shlokas. Specifically, it covers four topics that are at the essence of any spiritual scripture: what is the world, who am I, what is God or what transcends the world and me, and what is the relationship between me, the world and God.
 
The chapter first addresses the nature of the world. Our existence in this world is illustrated using an upside down tree, similar to a family tree. The root of this tree is Ishvara wielding the power of Prakriti, the saguna brahman, the eternal essence with attributes. Samsaara, our existence on this world, is the outward growth of this tree. This growth is fueled by sense objects which are in the form of sprouts or buds. Each sense object generates desires, which generates actions, which bind us to the branches of the tree.
 
The only way to rid ourselves of this endless cycle of desire and action is to cut the tree using the weapon of dispassion. The best way to cultivate dispassion is to go straight to the source of the tree, to take refuge in Ishvara. A seeker who wants to do so needs a list of qualifications such as freedom from pride and delusion. Only then will the seeker reach the abode of Ishvara, which is the state of self realization and liberation.
 
Next, the chapter addresses the state of the jeeva, the individual soul, the “I”. From an absolute standpoint, there is one eternal essence, one consciousness, one self, one "I". But just like space seems like it is divided into many through walls, this eternal essence is as though divided into multiple "I"’s through apparent limitations or upaadhis.
 
By attaching itself to upaadhis of the mind and the sense organs, an illusory self is created that imagines itself to be the jeeva, the individual soul. It takes up a new human body to exhaust the desires in its mind, but unfortunately picks up new desires and takes up yet another human body once the old one ceases to function. Only those individuals who have the eye of wisdom, who have assimilated the teaching of the scriptures after purifying themselves with karma and bhakti yoga, recognize the non-divided nature of the self. All others are living in delusion.
 
The third topic, the nature of God or Ishvara, is taken up next. We learn that Ishvara is not some remote figure, but pervades every aspect of the universe. Ishvara provides awareness or the faculty to know. He provides energy through the sun, the moon and fire. This energy is circulated throughout the universe in the form of Soma or nectar, and also used for medicinal purposes. Metabolism, the faculty to extract energy from this food in the form of Soma, is manifested through Ishvara as the Vaishvaanara fire. Ultimately, all memory and knowledge is possible through Ishvara who is resides in the hearts (intellect) of everyone.
 
The fourth topic deals with relationship between the individual, the world, and God. If we trace the energy source of a tiny mango sapling, and of a 100 megawatt solar power plant, we reach the same source - the sun. Similarly, if we mentally remove the apparent limitations, the upaadhis, the names and forms behind the individual, the world and of Ishvara, we find the foremost person, the Purushottama, the pure unadulterated eternal essence. It is beyond the perishable visible world and the imperishable seed of the visible world which is Prakriti.
 
In other words, we learn that the "I" in us is the "I" in everyone, the self of all.