An old epic poem called "The Bhagavad Gita" describes a discussion between the warrior Arjuna and Krishna, who is God manifested as a charioteer. The conversation happens right before a very important battle, and it shows Arjuna the important lessons he needs to learn to change the course of the battle. At the end, Krishna shows the warrior his true celestial form and tells him to look for the perfection of life for everyone. This book  is one of the most significant Hindu texts and offers advice on good living as well as yoga posture instructions and dense moral discussion.