The Gita is set in a narrative framework of a dialogue between Pandava prince Arjuna and his guide and charioteer Krishna. At the start of the Dharma Yudhha (righteous war) between Pandavas and Kauravas, Arjuna is filled with moral dilemma and despair about the violence and death the war will cause in the battle against his own kin. He wonders if he should renounce and seeks Krishna's counsel, whose answers and discourse constitute the Bhagavad Gita. Krishna counsels Arjuna to "fulfill his Kshatriya (warrior) duty to uphold the Dharma" through "selfless action". The Krishna–Arjuna dialogues cover a broad range of spiritual topics, touching upon ethical dilemmas and philosophical issues that go far beyond the war Arjuna faces. (www.wikipedia.org)
The Upanisads are the latter part of the oldest scriptures of Hinduism, the Vedas, that deal with meditation, philosophy, and ontological knowledge; other parts of the Vedas deal with mantras, benedictions, rituals, ceremonies, and sacrifices. Among the most important literature in the history of Indian religions and culture, the Upanishads played an important role in the development of spiritual ideas in ancient India, marking a transition from Vedic ritualism to new ideas and institutions. Of all Vedic literature, the Upanisads alone are widely known, and their central ideas are at the spiritual core of Hinduism. (www.wikipedia.org)