Arjuna s’ role in Bhagavad Gita symbolizes journey of a spiritual seeker who seeks reaching God in one’s lifetime. Even while facing the enemy in the battle of Mahabharata head-on Arjuna was so engrossed in thoughts of God Almighty that he suddenly reached state of enlightenment and in those moments the sermon of Bhagavad Gita was delivered to him by Lord Krishna.
Metaphorically, allegorically Lord Krishna is none other than soul atman, the spirit consciousness existing in our heart as Prana energy; we can also call as Sap of life. In absence of soul atman, spirit within a human body means the body is dead. We lived due to existence of soul atman within. In fact the present human journey is taken by soul atman within and human form is but a medium for consciousness within regain its true inner self, become a pure soul atman.
Amongst all Pandava princes Arjuna was the only candidate who sincerely and truthfully indulged in spirituality to reach cosmic end of life, prime reason why sermon of Bhagavad Gita was delivered only to him and none else.
Lord Krishna in Bhagavad Gita explicitly says teachings of Bhagavad Gita must never be rendered to one disinterested. In Mahabharata Arjuna is the one who precipitated wisdom of Bhagavad Gita and presented it to mankind so that other human beings could also follow the same path to reach God in their lifetime.
It is an absolute fact of human life in Hinduism that state of enlightenment, self realization, god realization can be reached only by indulgence in teachings of Lord Krishna in Bhagavad Gita. One single scripture containing 700 shlokas verses suffices for entire humanity to reach God. Yet, there were no takers.
The original text of Bhagavad Gita with 700 shlokas verses in Sanskrit along with English and Hindi transliteration is available for mere $1 from Gita press, Gorakhpur, India. Gita press also has online presence and the books can be ordered from there.
Authentic commentaries on Bhagavad Gita by authentic writers are available with Gita press both in Hindi and English. Commentary on Bhagavad Gita by Adi Shankaracharya (an enlightened one) is also available.