The Bhagavad Gita.
^ Bhagavad Gita for the win!
I like what Gandhi said:
"The Gita is the universal mother. I find a solace in the Bhagavad Gita that I miss even in the Sermon on the Mount. When disappointment stares me in the face and all alone I see not one ray of light, I go back to the Bhagavad Gita. I find a verse here and a verse there , and I immediately begin to smile in the midst of overwhelming tragedies - and my life has been full of external tragedies - and if they have left no visible or indelible scar on me, I owe it all to the teaching of Bhagavad Gita."