Karna Vivada Parva or Karnopanivada Parva is the fifty fifth Upa Parva included in the fifth Maha Parva named as Udyoga Parva in Mahabharata.
The story of Mahabharata and the Bhagavata Purana were written by the sage Vyasa Maharshi. Vyasa was the teacher of Vaishampayana Rishi and Krishna was depicted as the incarnation of God Vishnu in both of them. In Purana, devotion to God was described as the main theme. Here in Mahabharata, Arjuna had been depicted as the main hero; he was the father of the grandfather of the listener of the story, Janamejaya and he was free to ask any doubtful queries in between the narrations of his ancestor’s life. After the actual events, more than one century time had already passed then, and the Ashwamedha Yaga was going on at the palace in the Town of Takshashila.
Kripa was the old family priest of Pandavas and Krishna instructed him to give good education to Pareekshit, then child, the Prince of Abhimanyu was being very young. Krishna blessed Kripa to be living always as a Chiranjeevi. After the great Mahabharata war, the palace at Hastinavati needed renovation and was getting it done slowly. The Dwapara Yuga had ended and after Krishna Niryana, Kaliyuga had started. Kripa had left for his penance at Himalaya in Badarikashram with Veda Vyasa Maharshi, after completion of his teachings to Pareekshit and installing him on the throne as king. Pareekshit had shifted his palace to Takshashila but died at the age of sixty.
Later, the young Janamejaya had assumed the kingship at Takshashila with the blessings of his people. After stopping the Sarpa Yaga, this Ashvamedha Yaga was started in this palace of Janamejaya at the Town of Takshashila. There was no animal sacrifice in that yaga, but this story of ‘Mahabharata’ was narrated by Rishi Vaishampayana, as a virtuous hearing to pass the holy time for the king and the Suta Puranikas of Naimisharanya had also attended the auspicious occacion.
Vaishampayana continued his narrations to Janamejaya as follows.
What Krishna discussed with Karna and how did Sanjaya narrate it to Dritarashtra?
After coming out of the court hall with Satyaki and Kritavarma, Krishna desired to ascend his chariot accompanying Karna and hence called him to come along with him. So Karna came and sat near Krishna on the chariot and started their discussions. Krishna told Karna about his birth stories and Karna agreed with him but also replied that the old events were known to him. Krishna requested Karna to join with Yudhishtira and start to rule as an Emperor. Yudhistira would be the prince and all Pandavas would be his servants. Being the eldest son of Kunti, he could shine as an Emperor in the whole world. He could lead a pleasant, glorious future life and avoid the war. Sanjaya told it to Dritarashtra later.