Read the auspicious discussion which took place on the battlefield before the Mahabharata War started.
The Bhagavad Gita is a dialogue between Shri Krishna, Shri Vishnu's eigth incarnation, and his friend and disciple, King Arjuna.The Bhagavad Gita is composed of 700 Shlokas arranged in 18 chapters. It is one of the best-known philosophical texts of Hinduism, and is said to be translated in over 40 languages.
The entire bhagavad Gita is a dialogue between Shri Krishna and King Arjuna which took place before the war commenced. The army assembled by the five Pandava brothers was to fight the battle against the army of the Pandava's cousin, King Duryodhana. Duryodhana had robbed them of their rightful kingdom and refused to participate in any plans for a compromise.
Pandava army was led by 5 brothers namely, Yudhistara, Bhima, Arjuna, Nakula and Sahadev. Arjuna, the third of the five Pandava princes, was perhaps the greatest and most renowned warrior-hero in the Pandava army. His chariot was led by Shri Krishna himself who guided him with his excellent strategies during the course of the war.
Kaurava army consisted of 100 Kaurav brother with Karna, Bhishma Pitamaha, Guru Drona and other warriors loyal to duryodhana. They were the teachers of Pandavas but fought against them due to their sworn oath to serve the kuru kingdom. Seeing his teachers and cousin on the opposite side, arjuna was grief sticken and decided to drop his weapons. Seeing this, Shri Krishna decided to teach arjuna the importance of war and why it must be fought.
Below are the 18 chapter of Holy Srimad Bhagavad Gita with transliteration and their english meaning sourced from a book called The Bhagavad Gita