The Bhagavad-Gita (lit. "Song of God") is a portion of the much larger Mahabharata, the great history of the descendants of King Bharata. That great epic relates the events which led up to the speaking of the Bhagavad Gita. In order to set the stage for our examination of the Song of God, a brief recounting of these events is in order.
Long long ago, in the celestial or heavenly spheres, there were eight Vasus. These deities are the attendants of Lord Indra (the deva or god of rain and thunder, often referred to as the chief of the gods). Once these Vasus visited the earth and happened upon the sacred hermitage of the renown sage Vashistha, who was not at home at the time. Feeling weary from their journey, the Vasus approached Vashistha's kamadhenu, or cow of plenty. Being amazed at the cow's ability to supply unlimited amounts of milk of its own accord, the devas decided to steal her. When the sage returned and discovered what had transpired, he cursed the Vasus, forcing them to take birth on earth as men.
The Vasus, appalled at the prospect, approached the sage and begged his forgiveness. Vashistha refused to reverse his curse however. To console them, he suggested that if they could find a women who would willingly birth them, then immediately kill them, they could resume their heavenly occupations more quickly.
The Vasus besought the aid of Gangadevi (Goddess of the sacred river Ganges). They told her of their plight and she agreed to act as their mother and executioner.
After some time Gangadevi, in the form of a beautiful women, met King Santanu, who was walking along the banks of the Ganges. Upon seeing the beauty of the goddess, he proposed marriage. This request she quickly granted, on the proviso that he never interfere with anything she did, regardless of how abhorrent her actions might appear. The King agreed and the two were wed.
One by one the Vasus were born to Gangadevi and, much to the horror of the king, one by one she took their life by throwing them into the river Ganges. That is, until the eight son was about to be destroyed.
As Gangadevi prepared to throw her eighth child into the river, the king forbade her, saying that he could bear no more. This son, he demanded, must be allowed to live.
The goddess of the holy river smiled and replied that as the king had broken his promise to her she must leave him. Handing him the baby she explained the nature of the children and why she had destroyed them. Thereafter she vanished.
The king named the lad Devavrata, one who takes a divine vow, and raised him with love and fairness. This son proved to be a good and faithful child of his father.
After many years, King Santanu fell in love with a certain fisherman's daughter. Requesting her hand in marriage, the fisherman declined, stating that as the king already a son, any son born of his daughter could not become successor to the throne. The broken-hearted king left.
In time Devavrata found out the cause of his father's dejection and, as a loyal son, approached the fisherman with a solution to the problem. He offered to renounce his claim to the throne and take a vow of life-long celibacy, lest his progeny seek the throne. Thus his name proved to be a prophecy regarding this divine vow. The devas were so pleased with his renunciation that they renamed him Bhishma the Terrible.
The fisherman approved of this arrangement, and allowed his daughter to wed the king.
King Santanu and the fisherman's daughter, Satyavati, were wed and in time had two sons, Chitrangada and Vichitravirya. Each of these died early and without offspring due to poor health. Queen Satyavati, wishing to leave an heir to the throne, approached Bhishma for sex. He, of course, refused to comply due to his vow of celibacy. The wives of the two deceased princes then married and had two sons, Dhritarashtra and Pandu.
Again these sons were weak, the prior being born blind and the latter sickly. Due to the elder son's blindness, Pandu ascended the throne.
In time Dhritarashtra produced one hundred sons, known as the Kauravas ("descendants of King Kuru"), and Pandu produced five: the Pandava princes Yudhisthira, Bhima, Arjuna, Nakula and Sahadeva.
All the royal princes, the Kauravas as well as the Pandavas, were well trained in the military sciences by Drona, who was said to the most expert military strategist then living.
Not long after this, the Bharata King Pandu unexpectedly died. After his death Dhritarashtra, with help of Bhishma, ascended the throne and raised the Pandavas, who were still quite young, along with his own one hundred sons. In time the Pandavas became righteous and very powerful, whereas the sons of Dhritarashtra grew corrupt, though also quite puissant.
Out of envy Duryodhana, the eldest Kaurava, sought to murder the Pandavas in order to ascend the throne unchallenged. Through a long series of fascinating and inspiring events, faithfully recorded in the Mahabharata, the situation steadily worsened. In time the eldest Pandava, Yudhisthira, won dominion over the kingdom. This defeat infuriated not only Duryodhana, but all the Kauravas.
Now it happened that Sri Krishna, Who is the Blessed One Incarnate, was living on the earth at that time. Sri Krishna favored a peaceful resolution of the conflict, which the Pandavas also sought, and so became their representative in the negotiations.
The Pandavas, who were the rightful heirs to the throne, offered to give up everything in the name of peace. They requested only five villages, one for each of them. Duryodhana replied that he would not give them so much as an inch of land. Due to his power-mad mentality, war became inevitable. Through Sri Krishna's mediation, an agreement between Duryodhana and the Pandavas was established whereby all of Krishna's military might (He was king of Dwaraka), went to the Kauravas, whereas Krishna Himself became the unarmed charioteer of the righteous Pandava prince Arjuna.
On the appointed day both sides took their place on the field of battle. King Dhritarashtra, being blind, requested the sage Sanjaya, to narrate the battle scene for him. Sanjaya was, according to scholars such as Swami Chidbhavananda, temporarily endowed with the powers of intuitive cognition or second sight (which is sometimes called remote viewing) so that he could ascertain the events and dialogues of the battlefield. Srila Bhaktivedanta Swami comments: Sanjaya was a student of Vyasa, and therefore, by the mercy of Vyasa, Sanjaya was able to envision the Battlefield of Kurukshetra even while he was in the room of Dhritarashtra.
Here Ends the Introduction to Srimad Bhagavad Gita.