The first chapter demonstrated the nature of Prince Arjuna’s sorrow on the battlefield. He was confused because he believed that he would be miserable irrespective of how he chose to act. At that point, he surrendered to Shri Krishna to guide him.
In the second chapter, Shri Krishna gave the highest Knowledge about the Supreme Reality. He explained elaborately to Arjuna that his sorrow is because of delusion born out of ignorance of his true nature. Shri Krishna reveals that the Self in Arjuna (and all of us) is the same as the Supreme Reality. This Supreme Reality is Brahman, which is eternal, changeless, and limitless. Experiencing this Knowledge is the goal of spirituality.
At the beginning of the third chapter, Arjuna is confused. Krishna gave him the highest Knowledge. Yet, he still insisted that Arjuna perform his duties as per the doctrine of Karma Yoga. He was not encouraged to pursue the path of Knowledge (Jnana Yoga) to be a man of wisdom. The initial confusion that Arjuna faced in the first chapter still remained. He was not sure about what action to undertake. Shri Krishna then explains how Karma Yoga purifies the mind. This purification helps one realize the Knowledge of Self through study, reflection, contemplation, and meditation.
The fourth chapter begins with an intent to invoke love and reverence in the heart of Arjuna towards Shri Krishna. A student finds it challenging to accept ideas from his teacher without love and reverence for the teacher. Shri Krishna already knew Arjuna was fit to receive this knowledge. So, he wanted to remove lingering doubts in the student’s mind.
Chapter 4, Verse 1
श्रीभगवानुवाच
इमं विवस्वते योगं प्रोक्तवानहमव्ययम् ।
विवस्वान्मनवे प्राह मनुरिक्ष्वाकवेऽब्रवीत् ॥४.१॥śrībhagavānuvāca
imaṁ vivasvate yogaṁ proktavānahamavyayam,
vivasvānmanave prāha manurikṣvākave’bravīt. (4.1)4.1. The Lord said: I taught this eternal Yoga to Vivasvan, who passed it on to Manu; and Manu taught it to Ikshvaku.
Vivasvan is the Sun God. Sun is the first to be created, without which no other being can survive. He is an embodiment of selfless work who does his duty precisely without bothering about the praises or curses. Every bit of what the Sun does is for the welfare of all, without any ego or selfish desire.
Shri Krishna says that he gave this art of right action to Vivasvan. Vivasvan gave this knowledge to Manu, the first wise man amongst mankind, and Manu taught Ikshvaku, the forefather of Arjuna. In this way, Shri Krishna glorifies this knowledge as eternal and imperishable. It has been carried on through generations of kings.
Chapter 4, Verse 2
एवं परम्पराप्राप्तमिमं राजर्षयो विदुः ।
स कालेनेह महता योगो नष्टः परन्तप ॥४.२॥evaṁ paramparāprāptamimaṁ rājarṣayo viduḥ,
sa kāleneha mahatā yogo naṣṭaḥ parantapa. (4.2)4.2. O Parantapa (Scorcher of the foes), the saintly kings thus received this knowledge in a continuous tradition. But with the long passage of time, this Yoga has been lost in this world.
This knowledge was passed down as a continuous tradition. It was transferred in succession from Vivasvan to Manu. Then, it went from Manu to Ikshvaku and to Nimi. And so on. All spiritual kings were very familiar with the practice of karma yoga to reach perfection. These kings would hand over the kingdom to their sons after reaching a certain age. They would then retire to the forest to contemplate and meditate.
Yet, this Knowledge was lost in time as everything changes in time. In due course, people were infected by greed, anger, pride, etc. When the knowledge reached unfit students, they couldn’t transfer the teachings in their true essence to future generations. Here Shri Krishna gives Arjuna (and all of us) hope. He shares this knowledge once again in its purest form even for all of us.
Chapter 4, Verse 3
स एवायं मया तेऽद्य योगः प्रोक्तः पुरातनः ।
भक्तोऽसि मे सखा चेति रहस्यं ह्येतदुत्तमम् ॥४.३॥sa evāyaṁ mayā te’dya yogaḥ proktaḥ purātanaḥ,
bhakto’si me sakhā ceti rahasyaṁ hyetaduttamam. (4.3)4.3. The same ancient Yoga which is the Supreme Secret has been revealed to you today because you are My friend and My devotee.
Shri Krishna says to Arjuna that he is giving him the same glorious knowledge (which was lost in time). And he is doing so because Arjuna is a dear friend and His devotee. Arjuna has totally surrendered to Shri Krishna, with immense love and respect for Him. Additionally, he has a very friendly relationship with Shri Krishna as they grew up together. The ease in their relationship along with Arjuna’s devotion made him a fit student to receive this knowledge from Shri Krishna.
Secret in this context doesn’t mean that it is not to be shared with anyone (like how the pundits have interpreted it). The scriptural study is considered secret because no matter how wise one is in understanding the world, he can never understand the substratum behind the universe on his own, until some great master points that out to him.
Chapter 4, Verse 4
अर्जुन उवाच
अपरं भवतो जन्म परं जन्म विवस्वतः ।
कथमेतद्विजानीयां त्वमादौ प्रोक्तवानिति ॥४.४॥arjuna uvāca
aparaṁ bhavato janma paraṁ janma vivasvataḥ,
kathametadvijānīyāṁ tvamādau proktavāniti. (4.4)4.4. Arjuna said:
You were born much after Vivasvan. How am I to understand that you taught this Yoga to him in the beginning?
Arjuna is confused. Shri Krishna is standing right in front of him and is only a few years older than him. How could he have taught Vivasvan, the Sun, who was there long before them?
Arjuna is not doubting what Shri Krishna is saying. He is confident that he will get answers to all his questions from his teacher and friend Shri Krishna. He asks Shri Krishna for clarification. How can someone born much later teach an individual who existed before his birth?
Shri Krishna in the following verses starts discussing one of the important concepts in Sanatana Dharma, avatara.
Bluishmuse 