The Vedas (and, to some schools of thought, the Upanishads) are considered shruti (“what is heard”) by Hindus in that the works are considered eternal knowledge communicated by the Divine and heard by sages who then preserved them. The Mahabharata, the Gita, and the other great epic, the Ramayana, are considered smritis(“what is remembered”) as they are regarded as works written by human beings drawing on past history, lore, and tradition. It should be noted that, in some Hindu sects (such as the Hare Krishna movement), the Gita is understood as shruti on par with the Vedas, but this claim is not commonly accepted.
The Mahabharata begins with the story of the king Shantanu of the Kuru clan who sets in motion a series of events whereby his second wife, Satyavati, comes to control the kingdom along with their son Devavrat (also known as Bheeshm). Bheeshm captures three princesses from another kingdom as wives for his half-brother Vichitravirya, who was to be crowned king. One of these was released and the other two married Vichitravirya who then died without producing an heir. The two princesses were then married to Satyavati’s son from her first marriage, the sage Vyasa, in order to preserve the Kuru line. One of the princesses gave birth to Dhritarashtra (who was born blind) and the other to Pandu. Vyasa then had a third son with a maid of the ladies who was called Vidur. All three boys showed exceptional skills in different areas of government.
In time, Dhritarashtra was married to the princess Gandhari and Pandu to another named Kunti. The two princes and Vidur consolidated the rule of the kingdom and, when they came of age, Pandu became king even though Dhritarashtra was older because a blind man could not legally rule. Pandu reigned well and, when all seemed in order, Pandu requested leave and went off to live in the woods with Kunti and his lesser wife Madri. Years later, Kunti returned with her five sons who had been born in the wilderness – Yudhishthira, Bhima, Arjuna, and the twins Nakula and Sahadeva – along with the corpses of Pandu and Madri whose deaths have brought the family back to the kingdom. These sons (known as the Pandavas) are attributed to Pandu as father but, actually, each was conceived by the union of Kunti and Madri with different gods.
While Pandu and his wives were gone, Dhritarashtra and Gandhari had produced 100 children, the oldest of whom was Duryodhana, known as the Kauravas. Rivalry between Duryodhana’s side of the family and the five sons of Kunti informs the rest of the story which finally results in the armies of the two branches of the family facing each other at the Battle of Kurukshetra.
This is where the action of the Gita takes place, just before the battle is about to begin. Krishna, in his present incarnation, is related to both sides and declares he will fight for neither but assist both. He serves as Arjuna’s charioteer and, as both armies move into position for battle, Arjuna asks Krishna to drive him to the center of the field so he can look upon all of those who are so eager for war. When Krishna obliges, Arjuna sees his friends, relatives, old teachers, counselors, all of the people who played a part in his life and made him who he is. He tells Krishna that he cannot be a part of any action that will result in so much death and misery. He throws down his great bow and declares he will not fight.
Prior to the battle, Krishna endowed the counselor Sanjaya with a kind of second sight so that, even miles away, he could see everything taking place on the battlefield and report it precisely to Dhritarashtra. The Gitabegins with Dhritarashtra asking Sanjaya what is happening at Kurukshetra; Sanjaya then narrates Arjuna’s despair, Krishna’s response, and the whole of their dialogue which finally culminates in Arjuna’s understanding of the nature of existence, his place in the cosmic order, and why he has to take part in the coming battle.
The Mahabharata then continues as Arjuna picks up his bow to fight. The Pandavas win but at the cost of almost their entire army. Duryodhana and the Kauravas are all killed. Yudhishthira and his brothers then rule the land for 36 years before abdicating in order to pursue peace in their final days in the Himalayas where they die and are brought to paradise.