The story about the fight between Jambavan and Shri Krishna is related to the Syamantaka gem, a precious jewel that was given to King Satrajit by the Sun god. The gem had the power to produce gold and protect its owner from diseases and enemies. Satrajit gave the gem to his brother Prasena, who wore it around his neck and went hunting in the forest. There, he was killed by a lion, who took the gem and ran away. The lion was then killed by Jambavan, a powerful bear-king who was a devotee of Lord Rama in his previous incarnation. Jambavan took the gem and gave it to his son as a toy.

Meanwhile, Shri Krishna was suspected of killing Prasena and stealing the gem by Satrajit and others. To clear his name, Krishna tracked down Prasena’s footsteps and found his corpse. He followed the trail of the lion and reached Jambavan’s cave, where he saw the gem shining in the dark. He entered the cave and tried to take the gem, but Jambavan’s son resisted. Jambavan heard the commotion and came to fight with Krishna.

The combat between Krishna and Jambavan ensued for 27/28 days (per Bhagavata Purana) or 21 days (per Vishnu Purana), after which Jambavan began to grow tired. Realizing who Krishna was, Jambavan submitted. He recognized Krishna as his lord Rama, who had promised to fulfill his desire to fight with him in his next incarnation. He apologized for his mistake and worshipped Krishna. He also offered his daughter Jambavati as a bride to Krishna, who accepted her with pleasure. Krishna returned the gem to Satrajit and cleared his reputation. He also married Satyabhama, another daughter of Satrajit, who was attracted to him.

This is the summary of the story about the fight between Jambavan and Shri Krishna.