The Vedas (Rig, Yajur, Sama, Atharva) are the oldest scriptures. The Upanishads discuss the soul and ultimate reality. The Ramayana tells of Rama, and the Mahabharata (with the Bhagavad Gita) tells of the Pandava and Kaurava war. The Gita is Krishna's advice to Arjuna: do your duty without attachment to results.