Recap: Shri Krishna spoke to Arjuna about the transiency of the world, about the difference between the ãtmã and the body, and about the true form of the ãtmã. This knowledge is what is meant by sãnkhya jnãn. Now let us see what happens thereafter...

A Pledge to Teach Yoga
Up till now, Shri Krishna had explained sãnkhya jnãn. Thereafter, explaining a very important principle, he says,“एषा तेऽभिहिता सांख्ये बुद्धिर्योगे त्विमां श्रृणु । बुद्ध्या युक्तो यया पार्थ कर्मबन्घं प्रहास्यसि ॥” – ‘Eshã te’bhihitã sãnkhye buddhiryoge tvimãm shrunu, buddhyã yukto yayã Pãrtha karmabandham prahãsyasi.’ – ‘O Parth, I have explained sãnkhya jnãn, I will now explain the knowledge of yoga. Listen carefully. By this knowledge you will be freed of all bonds’ (Gitã 2.39).
This is a pledge to teach yoga. Bhagwan himself has made this pledge. This is the source of the divine river of yoga. It is the first time that the word ‘yoga’ has been used in the Gitã. This divine river will henceforth continuously flow all the way to the last shloka of the entire Gita where we find the words ‘यत्र योगेश्वरः कृष्णः’ – ‘Yatra Yogeshvaraha Krishnaha’ (Gitã 18.78).
Thus, having explained sãnkhya jnãn to Arjuna, Shri Krishna says that he is concluding the topic and beginning another. However, hereafter, right till the end of the Gitã, Shri Krishna does not say, ‘I have finished talking about yoga and now I will talk to you about a third topic.’ Yoga continues to remain the main subject right to the end. Thus we can confidently state that ‘yoga’ is the major subject of the Gitã.

The Meaning of the Word ‘Yoga’
The word ‘yoga’ is derived from the verb root yuj. Sanskrit grammar shows various meanings of the root yuj: relation, attainment or union (युजिर्‌ योगे - yujir yoge); a state of trance or deep meditation (युज् समाघौ - yuj samãdhe); miraculous powers ( युज् ऐश्वर्ये - yuj aishwarye).
The Bhagavad Gitã illustrates all these meanings of yoga. The interesting thing is that the Bhagavad Gitã has directed all these meanings to Paramãtmã, and thus breathed life into them. Moreover, it has, with great ease, explicitly and undoubtedly proclaimed that Paramãtmã means manifest Paramãtmã, and that conviction in the form of manifest Paramãtmã is yoga.
The system of philosophy propagated by Maharshi Patanjali is also focused on yoga. The term ashtãng yoga is widely used. It is this that Patanjali has described in detail, and thus his school of thought became known as Yogadarshan. He commences with the words ‘अथ योगानुशासनम्’ – ‘Atha yogãnushãsanam’ – ‘Hereforth commences an explanation of yoga’ (Yogasutra 1.1). Thereafter, he immediately defines the word ‘yoga’.. ‘योगश्र्चित्तवृत्तिनिरोघः’– ‘Yogashchittavruttinirodhaha’ – ‘Yoga means to restrain the mind’ (Yogasutra 1.2). The aim is to withdraw the mind from wandering to the sensory pleasures. As he continues, he calls this yoga samãdhi. The Bhagavad Gitã links this samãdhi yoga with the manifest form of Paramãtmã. When one focuses completely on the manifest form of Paramãtmã, one has accomplished samãdhi. Such a samãdhinishth person is called a yogi. This point has been reiterated by Shri Krishna repeatedly throughout the Gitã.

Being Solely Devoted to the Manifest
Form of Paramãtmã Is Yoga
Let us look at an example from the sixth adhyãy. A clear description of yoga is given in this adhyãy, revealing the qualities of a true samãdhinishth yogi. Shri Krishna says, ‘, ‘सर्वभूतस्थमात्मानं सर्वभूतानि चात्मनि । र्इक्षते योगयुक्तात्मा सर्वत्र समदर्शनः॥’ – ‘Sarvabhootasthamãtmãnam sarvabhootãni chãtmani, eekshate yogayuktãtmã sarvatra samadarshanaha.’ – ‘One who can see Paramãtmã in all living things, one who experiences that everything resides in Paramãtmã, one who can see Paramãtmã equally in everything is one with yoga’ (Gitã 6.29). This is a well accepted basic definition of yoga. The Gitã then expands this definition to include conviction in manifest Paramãtmã,‘स योगी मयि वर्तते’ – ‘Sa yogee mayi vartate’ – ‘Such a yogi is ever engrossed in me’ (Gitã 6.31). Constantly remembering manifest Paramãtmã is the highest level of samãdhi.
This is, in fact, the very aim of the endeavour of ashtãng yoga. However, often, the means become the goal and the ultimate goal is forgotten. The endeavour of yoga (yoga sadhana) is an example of this. Many do these endeavours with the aim of experiencing samãdhi, but they forget that true samãdhi is to be completely engrossed in Paramãtmã. Such endeavours are fruitless. They are a waste of time and energy. Krishna educates Arjuna to prevent him making such a mistake.
Shri Swaminarayan Bhagwan has also explained true yoga sadhana in the same manner. He says, ‘A devotee whose chitt’s vrutti becomes focused on the form of God masters ashtãng-yoga without even attempting to master it’ (Vachanamrut, Gadhadã I 25).

The Scarcity of Yoga of Manifest
Paramãtmã
The secret of yoga is also revealed at the start of the seventh adhyãy. Shri Krishna says, ‘‘मय्यासक्तमनाः पार्थ योगं युञ्जन् मदाश्रयः। असंशयं समग्रं मां यथा ज्ञास्यसि तत्व्छृण’ – ‘Mayyãsaktamanãhã Pãrtha yogam yunjan madãshrayaha, asanshayam samagram mãm yathã gnãsyasi tachchhrunu.’ – ‘O Parth, listen to how you, who have your mind attached to me and have taken my shelter, will know me fully and explicitly by doing yoga sadhana’ (Gita 7.1). The message of this shloka is that to focus one’s mind completely on manifest Paramãtmã and to take his shelter is yoga sadhana; and to have undoubted conviction in the manifest form of Paramãtmã is its highest possible degree. However, not many reach this climax. Shri Krishna says, ‘मनुष्याणां सहस्रेषु कश्र्चिद् यतति सिद्धये । यततामपि सिद्धानां कश्र्चिन्मां वेत्ति तत्त्वतः॥’ – ‘Manushyãnãm sahasreshu kashchid yatati siddhaye, yatatãmapi siddhãnãm kashchinmãm vetti tattvataha.’ – ‘O Parth, only one or so in thousands attempt to attain this state, and of those who attempt only a few truly know me’ (Gitã 7.3).
This is indeed very true. It is not easy to do yoga sadhana, and to do those endeavours understanding Paramãtmã to be the ultimate goal is even harder. Further, to recognize the manifest form of Paramãtmã and understand him to be the ultimate goal of yoga is indeed very hard to accept. For example, Shri Krishna was an incarnation (avatar) of Bhagwan. Nevertheless, many people of the time believed him to be a mere shepherd’s boy. He had killed the demon named Madhu; this is a fact, and hence he is also known by the name Madhusudan. Yet, many did not understand his abilities and would say that this Krishna has never killed a demon named Madhu, but is called Madhusudan since he has emptied many honeycombs (madhu means honey). Thus, even some of the most powerful and influential people of the time failed to recognize him. Thus he says, ‘Yatatãmapi siddhãnãm kashchinmãm vetti tattvataha’ – ‘Only a few truly know me’ (Gitã 7.3).