Krishna explained karma yoga in the first six chapters and bhakti yoga from the seventh to the twelfth. In the last six chapters, He gives the details of jnana yoga. These contain the most philosophical teachings, entering into a new type of discussion that is both practical and profoundly metaphysical.
The first six chapters contain teachings pertaining to the individual soul and its relation to God. In the next six, the path to perfection, the union of the Jiva (individual consciousness) with Ishwara (universal consciousness), is dealt with. The harmony between the first and the second groups is discussed in the last six chapters. By a sudden shift of emphasis, Krishna introduces a teaching that is directly pertinent to the nature of the individual and the supreme.
Krishna speaks of the three-fold relationship of the knower, knowledge and the known, with the immediate reality that is presented to the senses, viz. the physical body. The body is the field where pleasure and pain are experienced, through the physical, mental and causal bodies. He who beholds the body as distinct from himself is the silent witness. This is called supreme wisdom.
Sages have declared that the five gross elements, ego, intellect, ten organs of perception and action, mind, five objects of sense, desire, hatred, pleasure, pain, physical body, and individual consciousness are modifications of the field. The Supreme Brahman (Purusha) is beginningless, unattached, supports all, and is free from the three gunas. It exists within and without all beings, too subtle to be known. All qualities are born of prakriti (nature). The body and senses are produced by prakriti. The experience of pleasure and pain is caused by the identification of purusha (individual soul - jiva) with prakriti.
Attachment to the qualities of nature causes birth. The spirit dwelling in the body is the same as the supreme spirit, the witness of everything. He who knows this secret, though he acts, is not born again. There are several methods to attain the knowledge of the Self. Some by deep meditation behold the supreme Self by consciously putting an end to the functions of the mind and intellect. Others by becoming a witness to the functions of body, senses, mind and intellect with an understanding that all these are products of prakriti. Some others by performing their duties with a detached spirit. Even those who are not aware of these methods and perform worship with devotion, lead a divine life by being good and doing good to others, also reach the Supreme.
Whatever exists is brought about by the union of purusha and prakriti (spirit and matter). The knower of Truth perceives the supreme consciousness existing equally in all beings. This Being never perishes when they perish. Such a devotee never injures others, knowing that his own Self is all-pervading and actionless. Thus, when one perceives that the manifold states of beings are centered in the One, he attains Brahman, i.e. merges into that supreme consciousness. Just as the ether pervading earth, water, fire and air, is not affected by their qualities, so also the Self (purusha) dwelling in the body (prakriti) is not affected by its qualities. As the one sun illumines the whole universe, the Atman illumines the whole field. Those who perceive the difference between the field and the knower of the field reach the supreme Self.
Chapter 13 teaches the benefits of being a witness, with a discriminative understanding that everything in the universe is a product of prakriti (nature). One should not identify oneself with the functions of one's intellect, mind, senses and body. One should not contaminate one's real nature (consciousness) with the products of prakriti, like the rain water which, after falling on and mixing with the earth, becomes muddy.
IMPORTANT VERSES IN CHAPTER 13
1. This body, O Arjuna is called the field; he who knows it is called the knower of the field, by those who know of them.
2. Do thou also know Me as the knower of the field in all fields, O Arjuna. Knowledge of both the field and the knower of the field is considered by me to be the knowledge.
1. What is the relationship between: Kshetra and Kshetrajna, Brahman and Maya, Pui Prakriti, Siva and Shakti?
2. What are the modifications of the 'field'?
3. Explain the three-fold relationship between the knower, the knowledge and the known.