17. Shree Krishna establishes the relationship between the body and the soul, by saying that the soul pervades the body. What does he mean by this? The soul is sentient, i.e. it possesses consciousness. The body is made from insentient matter, devoid of consciousness. However, the soul passes on the quality of consciousness to the body as well, by residing in it. Hence, the soul pervades the body by spreading its consciousness everywhere in it.
Some raise a question here regarding the location of the soul. The Vedas state that the soul resides in the heart:
The word hṛidi indicates that the soul is seated in the region of the heart. Yet, consciousness, which is the symptom of the soul, spreads throughout the body. How does this happen? Ved Vyas explains this concept as follows:
"Just as applying sandalwood to your forehead cools the entire body, similarly, the soul, although residing locally in the heart, infuses its consciousness throughout the body."
Again, someone may ask that if consciousness is a characteristic of the soul, then how does it spread into the body? This question has also been answered by Ved Vyas:
"Fragrance is a quality of the flower. But the garden where the flower grows also becomes fragrant." This means that the flower is able to pass on its fragrant quality to the garden. Likewise, the soul is sentient, and it also makes the dead matter of the body sentient, by pervading its consciousness in it.
18. The gross body is factually made from mud. It is mud that gets converted to vegetables, fruits, grains, lentils, and grass. Cows graze the grass and produce milk. We humans consume these edibles, and they transform into our body. So it is not an exaggeration to say that the body is created from mud.
And at the time of death, when the soul departs, the body can have one of the three ends: kṛimi, viḍ, or bhasma. Either it is burnt, in which case it is converted to ashes and becomes mud. Or it is buried, in which case insects eat it and transform it into mud. Else, it is thrown into the river, in which case the sea creatures make it their fodder and excrete it as waste, which ultimately merges with the mud of the seabed.
In this manner, mud undergoes an amazing cycle in the world. It gets transformed into edibles, bodies are made from these edibles, and the bodies return back into the mud of the earth. The Bible states: "For dust thou are, and unto dust thou shalt return. This phrase refers to the material body. Shree Krishna tells Arjun, "Within that material body is an eternal imperishable entity, which is not made of mud. That is the divine soul, the real self."
19. The illusion of death is created because we identify ourselves with the body. The Ramayan explains this as follows:
"If we dream of our head getting cut, we will perceive its pain until we wake up." The incident in the dream is an illusion, but the experience of the pain continues to torment until we wake up and dispel the illusion. Similarly, in the illusion that we are the body, we fear the experience of death. For the enlightened soul whose illusion has been dispelled, this fear of death vanishes.
One may ask that if nobody can kill anyone, then why is murder considered a punishable offense? The answer is that the body is the vehicle of the soul, and destroying any living being's vehicle is violence, which is forbidden. The Vedas clearly instruct: mā hinsyāt sarvabhūtāni "Do not commit violence toward anyone." In fact, the Vedas even consider killing of animals as a crime. However, there are occasions where the rules change and even violence becomes necessary. For example, in cases where a snake is approaching to bite, or if one is attacked with lethal weapons, or one's life sustenance is being snatched away, then violence is permitted for self-protection. In the present situation, what is appropriate for Arjun, violence or non-violence, and why? Shree Krishna will explain this to him in great detail, as the dialogue of the Bhagavad Gita progresses. And in the course of the explanation, priceless divine knowledge will be revealed to shed light on the subject.
20. The eternal nature of the soul has been established in this verse, which is ever-existing and beyond birth and death. Consequently, it is devoid of the six types of transformations: asti, jāyate, vardhate, vipariṇamate, apakṣhīyate, and vinaśhyati "Existence in the womb, birth, growth, procreation, diminution, and death." These are transformations of the body, not of the self. What we call as death is merely the destruction of the body, but the immortal self remains unaffected by all bodily changes. This concept has been repeatedly emphasized in the Vedas. The Kaṭhopaniṣhad contains a mantra almost identical to the above verse of the Bhagavad Gita:
"The soul is not born, nor does it die; it did not spring from something, and nothing sprang from it. It is unborn, eternal, immortal, and ageless. It is not destroyed when the body is destroyed." The Bṛihadāraṇyaka Upaniṣhad states:
"The soul is glorious, unborn, deathless, free from old age, immortal, and fearless."
21. A spiritually elevated soul quells the ego that makes us feel that we are the doers of our actions. In that state, one can see that the soul seated within actually does nothing. Such an elevated soul, though doing all kinds of actions, is never tainted by them. Shree Krishna is advising Arjun that he must elevate himself to that enlightened level, seeing himself as the non-doer, free from egotism, and perform his duty rather than shirk from it.
22. Continuing to explain the nature of the soul, Shree Krishna reiterates the concept of rebirth, comparing it to an everyday activity. When garments become torn and useless, we discard them in favor of new ones, but in doing so we do not change ourselves. In the same manner, the soul remains unchanged, when it discards its worn-out body and takes birth in a new body elsewhere.
The Nyāya Darśhan gives the following argument to prove the existence of rebirth:
It states that if you observe a little baby, you will find it sometimes becomes happy, sometimes sad, and sometimes fearful, without any apparent reason. According to the Nyāya Darśhan, the little baby is remembering its past life, and hence experiencing these emotions. However, as it grows up, the impressions of the present life are imprinted so strongly upon its mind, that they erase most past memories. Besides, the processes of death and birth are also so painful to the soul that they erase a substantial portion of the past life's memories.
The Nyāya Darśhan gives another argument in support of rebirth: stanyābhilāṣhāt. It says that a newborn baby has no knowledge of language. How then can a mother teach her baby to suckle her breast when she inserts it in the baby's mouth? However, the newborn child has drunk milk in infinite past lifetimes, even in animal forms, from the breasts, teats, and udders of innumerable mothers. Hence, when the mother puts her breast in the baby's mouth, it automatically starts suckling based on past practice.
Without accepting the concept of rebirth, the disparity between human beings becomes inexplicable and irrational. For example, let us suppose one man is blind from birth. If that person asks why he was punished in this way, what logical answer can be given to him? If we say it was a result of his karmas, he may argue that the present life is the only life he has, and therefore, there are no past karmas at the time of birth that should afflict him. If we say it was the will of God, it would also seem implausible, since God is all-merciful and would not unnecessarily want anyone to be blind. The only logical explanation is that the person was born blind as a consequence of karmas from past lives. Thus, from common sense and on the authority of the scriptures we are obliged to believe in the concept of rebirth.