Bhagavad-Gita, the most famous of all the ancient texts, is part of the 701 verses in the Mahabharata, one of the three major Sanskrit epics of ancient India and is said to be one of the three longest epic poems in the world.
Gita, as it is often called, recounted a dialogue between Arjuna, the reluctant combatant, and Krishna, spiritual adviser, shortly before the climactic battle on the battlefield of Kurukshetra where Krishna reveals that he is God.
If you want to study bhagavad gita, then you may visit this site. Basically, the dialogue between the two men, accounted for eighteen chapters of the text, explain the meaning and purpose of life and existence.
Just as the Christian teachings, the Bhagavad-Gita tells us that death is only shedding body and soul of man is immortal. This is the difference between focusing on what is temporary and that permanent.
According to Krishna, the origin of human suffering is the obsession with the desire that in the material world. Therefore, we must free ourselves from this desire to calm the mind through the discipline of both the senses and the intellect.
One must find a medium or balance. It is the purpose of life to free the mind and intellect of their involvedness with nature and to focus on the glory of himself by dedicating every action to the divine. This objective can be achieved through YOGA'S meditation, action, devotion and knowledge.