Gita series 50 - Bhagavad Gita Chapter IV.3-6:
Krishna continues. “You are my devotee and friend as well. Hence, this ancient yoga that is superior and secretive in nature was taught to you by me.” Arjuna asks Krishna “Vishvat was born much ahead of your birth. How can I comprehend that you had taught this yoga to him in the beginning.” Krishna replies. “Destroyer of enemies (Arjuna)! You and I experienced many births. You cannot recollect any of them whereas I know them all. Though I am eternal, indestructible and Lord of all living beings, abiding in my prakriti, I manifest due to my yoga maya.”Arjuna is not only Krishna’s disciple, but also His good friend. Generally yoga is taught through guru-disciple relationship as certain technicalities are to be learnt directly from a master. Intricacy of karma yoga is considered secretive in nature as proper learning of this yoga leads to self-realization. It frees a person to from the evil effects of bondage and leading him to feel the eternal bliss. Such secretive yoga according to Krishna is not to be shared with those who are not interested in God-realization.
The efforts of a master should not go waste in teaching this yoga to unworthy people. Karma yoga path is pursued by saints and sages who had attained liberation, from time immemorial and therefore Krishna calls this as ancient yoga. Krishna chooses Arjuna to teach this yoga because Arjuna has totally surrendered to Him and also has keen desire to advance spiritually. Divine directly imparts (divine commune) supreme knowledge, if one is making steady spiritual progress. Arjuna knows that Krishna is not an ordinary human but an avatar. There is no reason for Arjuna to know about Krishna’s teaching to Vishvat, who is known as sun god. But Arjuna wanted to listen to Krishna (divine commune) on karma yoga. Krishna is eternal and omnipresent. He existed in the beginning and will continue to exist forever even after annihilation. Divine is nothing but the Supreme Cosmic consciousness, from which souls are released to associate with prakriti causing creation. When this self illuminating cosmic consciousness is realised within during the process of mediation, it is called self-realization. Soul does not have the capacity to remember its previous incarnations. If it is vested with the capacity for such remembrance, it would have led to a chaotic situation in the universe. Such souls have only two options before them. One is to reborn again and again and to undergo the associated miseries.
Every one born in this universe, however good he might be has to certainly undergo sufferings, miseries and pains at some point of time during his living. The second option is to merge with the Brahman and the individual identity of the soul would be lost forever. Karma yoga is taught by Krishna enabling Arjuna to resort to the second option. Since karma yoga expounds on rebirths, it is considered as secretive in nature. If one is to learn the secrets of karma yoga, his karmic account should permit the same. Krishna teaches Arjuna not in His capacity as the God head, but as Arjuna’s guru. That is why He says that He was also born before. Before Krishna avatar Vishnu incarnated through other forms (ten avatars). He not only assumed different forms at different times, but also taught the secrets of karma yoga during those incarnations. In Krishna avatar, His teachings were in the form of conversation, whereas in His other avatars He had set examples by His actions.
Krishna being the Brahman (saguna Brahman) is fully aware of His previous incarnations and Arjuna being a mortal is not aware of his previous births. Soul of Arjuna remains covered by perishable sensory organs. Having incarnated in this universe, Krishna follows the principles laid down for others. He does not want Him to be known as God head, though He says that He is eternal, indestructible and Ishvara (supreme head) of the universe. Prakriti is Nature. A soul interacts with prakriti and attains a form to undergo the karmas embedded in it. But Krishna is not bound by karmic account. He controls prakriti, which is a product of mulaprakriti known as ‘avyakta’. But still He says that He abides in prakriti which is His own creation. He sets an example for karma yoga by following all prescribed rituals. His True nature is veiled by the effects of yoga maya known as worldly illusion. Everything in this universe is a mere reflection of God and only due to the influence of maya one is not able to realize the Truth. Krishna becomes both the cause and effect.