|The teaching of The Bhagavad Gita is summed up in the maxim "your business is with the deed and not with the result." When Arjuna, the third son of king Pandu (dynasty name: Pandavas) is about to begin a war that became inevitable once his one hundred cousins belonging to the Kaurava dynasty refused to return even a few villages to the five Pandava brothers after their return from enforced exile, he looks at his cousins, uncles and friends standing on the other side of the battlefield and wonders whether he is morally prepared and justified in killing his blood relations even though it was he, along with his brother Bhima, who had courageously prepared for this war. Arjuna is certain that he would be victorious in this war since he has Lord Krishna (one of the ten incarnations of Vishnu) on his side. He is able to visualize the scene at the end of the battle; the dead bodies of his cousins lying on the battlefield, motionless and incapable of vengeance. It is then that he looses his nerve to fight.|
The necessity for the arose because the one hundred cousins of the Panadavas refused to return the kingdom to the Pandavas as they had originally promised. The eldest of the Pandav brothers, Yudhisthir, had lost his entire kingdom fourteen years ago to the crafty Kaurava brothers in a game of dice, and was ordered by his cousins to go on a fourteen-year exile. The conflict between the Pandavas and the Kauravas brewed gradually when the Kauravas refused to return the kingdom to the Panadavas and honor the agreement after the fourteen-year exile, and escalated to a full scale war when the Kauravas refused to even grant Yudhisthir's reduced demand for a few villages instead of the entire kingdom. As the battle is about to begin, Arjuna, himself an acclaimed warrior, wonders how he could kill his own blood relatives with whom he had grown up as a child. He puts the battle on hold and begins a conversation with Krishna, one of the ten but most important incarnations of the Universal Hindu God, Vishnu. The Bhagavad Gita begins here and ends with Krishna convincing Arjuna that in the grand scheme of things, he is only a pawn. The best he could do is do his duty and not question God's will. It was his duty to fight. In convincing Arjuna, the Lord Krishna provides a philosophy of life and restores Arjuna's nerve to begin the battle -- a battle that had been stalled because the protagonist had lost his nerve and needed time to reexamine his moral values.
From Soumen De, "The Historical Context of The Bhagavad Gita and Its Relation to Indian Religious Doctrines." http://eawc.evansville.edu/essays/de.htm