The 18th chapter is the longest and is about moksha-sannyasa-yoga. It is also considered as a condensation of the previous 17 chapters.

Moksha represents the highest value in human existence and means liberation from the bondage of samsara. Sannyasa means giving up the feeling up doer-ship and the renouncement of ego.

According to Hindu tradition, four values guide human life – dharma, artha, kama, and moksha. Kama represents our desires, what we want to achieve. Artha represents the means to achieve those goals. Dharma represents a set of moral disciplines that guide and regulate our pursuit of artha and kama.

When we do not violate the path of dharma, then we can focus on something higher than artha and kama. That gives a new meaning to life. Life becomes more livable and enjoyable.
The realization of the imperfections of worldly enjoyments brings about the pursuit of something higher and transcendental. This divine discontent is called Parinama Dukha, and it is the springboard of spiritual wisdom.

These are two stages in our pursuit of the transcendental. First stage is one where we use the higher transcendental value to guide our daily life. At a higher stage, we attain the higher transcendental value and become a mendicant.

It is important to understand that in Gita, the principles of dharma, artha, kama, and moksha are primarily meant to be applied at an individual level (not at a macro, society level), for one’s own spiritual development in everyday life.

In Hindu tradition, there is a method of understanding the central theme of a book, which is comprised of six elements: Upakrama-Upasamhara (commencement, conclusion), Abhyasa (practice or reiteration), Apurvata (novelty), Phalam (practical utility), Arthavada (glorifying statement) and Upapatti (logical analysis).

Upakrama-Upasamhara – Normally, the beginning and conclusion should be the same. Gita does not begin with a focus on action It starts with Arjuna’s dilemma, which was due to ignorance. When this ignorance was removed through knowledge, he became a man of action. Arjuna’s last statement in the Gita is: “I am now free of all doubts. I shall act according to your instructions.”

Abhyasa – Gita repeatedly talks about efficiency, detachment, bhakti, and karma yoga. It emphasizes that jnanam is necessary to be active in an intelligent manner.
Apurvata – If something is stated in Gita but is not stated elsewhere, then it must be the central theme of Gita.

Arthavada - Gita ends with the glorifying verse: “Wherever the ideals of action and contemplation are present, there will be victory, prosperity, justice and stability of life.” This verse is a condensation of the 18th chapter.

Upapatti – Gita gives a logical analysis to drive the idea: “Live in this world, work for prosperity, but know that this alone will not bring lasting peace and happiness.”
The central theme of Gita combines the four values of dharma, artha, kama and moksha.

Based on dharma, we should live in this world. Over time, we realize the true status we should give to worldly life and start thinking of higher transcendental values.

3rd verse: “According to scholars and sages, performance of Yajna, dana and tapah should not be given up.”

Sannyasa does not mean being physically inactive. Lord Krishna states in the 3rd chapter: “A person who thinks who is active without the idea of yajna, that person gets bound to this world.” Yajna refers to any noble, unselfish activity done for the good of others and as an offering to God – activities done as yajna don’t lead to bondage. In the same chapter, Lord Krishna gives a warning: “A person who deliberately gives up his duties and imagines that he is going towards moksha, he is a hypocrite.” All great spiritual men of the word, such as Shankaracharya, were active.

The status of householder is supreme in Hindu tradition. It should be understood before we discuss sannyasa. Jainism and Buddhism are oriented towards sannyasa. Hinduism is not a negation of life. Rather it is a balanced approach towards life. Hinduism emphasizes that we should follow the four values: dharma, artha, kama, and moksha.

Hinduism gives a very high stature to mother and wife. One of Panini’s verses says: “If a husband performs a vedic ritual without his wife, it is considered incomplete.” Another verse says: “A house without a mother and wife is like a forest.”

There are two levels of Sannyasa. The primary is Mukhya sannyasa, where one takes to sannyasa because of one’s natural evolution. Buddha’s renunciation and Yajnavalkya’s renunciation in the Brihadaranyaka Upanishad are examples of such sannyasa. The secondary is Gauna sannyasa, where one is ordained into sannyasa by an institution.
Sannyasa does not mean physically giving up wealth and resources. One must give up one’s selfish sense of ownership. Without the ideal of renunciation, one won’t be able to use his resources for the good of others. The richest man can be a man of renunciation – King Janaka was one such example. On the other hand, the poorest man can be a man of tremendous attachment.

Besides Bhagavad Gita, there are other gems in the Mahabharata. One example is Vyadha Gita. Vyadha became a jivan mukta through his spiritual practices. Upon attaining the highest realization, he did not give up his profession as a butcher. He continued his secular activities, fully established in his true spiritual identity. His dialogue with another saint constitutes Vyadha Gita.

In the 11th chapter, Arjuna experiences the vision of the universal form of the divine. Lord Krishna shows that all the different creatures, animals, suns, moons, stars, galaxies, human beings, celestial beings – they all originate, exist, dissolve and re-emerge within that cosmic divine form. When Arjuna gets this vision, he is freed from all doubts. He understood that he is not just a body-mind complex with one life.