The Gandiva bow wielded by Arjuna and the Sudarshana Chakra wielded by Krishna throughout the Mahabharata both trace their origin to a single, dramatic event: the burning of the Khandava forest.
A fire god with an appetite problem
Agni, the fire god, had grown weak after being forced to repeatedly consume ritual offerings soaked in ghee, and sought to regain his strength by consuming the Khandava forest entirely – a task complicated by Indra, who protected the forest because his friend, the serpent king Takshaka, lived there.
Payment offered in advance
Agni approached Krishna and Arjuna for help defending the forest-burning against Indra’s interference, and in exchange, arranged for them to receive divine weapons perfectly suited to the task: Arjuna received the Gandiva bow along with two inexhaustible quivers, and Krishna received the Sudarshana Chakra, the discus that would later prove decisive in multiple critical moments across the epic.
A side effect that mattered later
During the burning, the demon architect Maya Danava was spared by Arjuna in exchange for his skills, and Maya later built the magnificent Maya Sabha for the Pandavas – the very palace whose illusions would trick Duryodhana into a humiliating fall and fuel the resentment that helped trigger the eventual war. What began as a favor for a hungry fire god ended up equipping both Krishna and Arjuna with their signature weapons and setting in motion the palace rivalry that would define the rest of the story.