Though Krishna, transcendent, exists beyond the limits of time, space, and matter, He had come to this world to play the role of Arjuna's charioteer--and to enlighten him.
At the onset of a battle, a battle between Arjuna and his own friends and relatives, Arjuna lost his composure. Surveying the two armies, he was overwhelmed by the pointlessness of what was about to occur. His skin shivering, his mind reeling, tears welling into his eyes, he dropped his bow and sank to the seat of the chariot

Then, in the midst of the two armies, Lord Krishna spoke to Arjuna the words that have come down to us as the book known as Bhagavad-gita.

Lord Krishna spoke about the meaning of life, the subtle workings of creation, and the understanding of a self- realized soul. He spoke of the science of yoga in all its forms--the path of work, the path of knowledge, the path of mysticism, the path of devotion.

And at last Lord Krishna revealed Himself before Arjuna as the source of everything, the eternal form of the Supreme, the Personality of Godhead.