Once Narada took Dharmaraja around both hell and heaven. In the heaven, Dharmaraja saw Indra and bowed to him. He then told Narada, “How much punya this person must have accumulated to get the position of Indra!” Narada said, “Dharmaraja, look properly. It is Duryodhana who has got the rank of Indra.” Seeing this Dharmaraja thought to himself, “If this villain can become Indra, what exalted position my generous, elder brother Karna would have got?” So thinking, he asked Narada to take him immediately to Karna. Narada took him to hell. There, seeing a person being tortured, Dharmaraja said, “How many bad deeds this person must have committed! Poor chap, I cannot bear to see him suffer.” Narada said, “Dharmaraja, he is your generous brother Karna.” Hearing this, Dharmaraja was surprised and was sad. He said, “God is biased. If He deceives like this, why blame human beings for doing wrong things?” Narada said, “But Karna was a traitor.” When Dharmaraja asked how could it be, Narada said, “When Karna was bemoaning that he had no relatives and he was an orphan, Duryodhana consoled him, acknowledged his capabilities and made him the king of Angarajya. Karna was happy and promised Duryodhana that he would kill all the enemies of Duryodhana. Placing his faith in Karna, Duryodhana did not worry too much when the war was declared. But before the war, Krishna sent Kunti to Karna. Kunti asked for some concessions from Karna, whose heart melted at his mother’s prayers and he promised to safeguard Pandavas. Accordingly, he protected Nakula and Sahadeva from Duryodhana. He also did not kill Arjuna when he had the opportunity to do so. This paved the way for the defeat and death of Duryodhana. For this treason, he is in hell.”
"‘Karna, the mighty bowman, that foremost of all wielders of weapons for whom thou art grieving, has also attained to high success. Behold, O puissant one, that foremost of men, viz., the son of Surya. He is in that place which is his own, O mighty-armed one. Kill this grief of thine, O chief of men.
O son of Pritha, thy brothers, O king, were not such as to deserve Hell. All this has been an illusion created by the chief of the gods. Without doubt, all kings, O son, must once behold Hell. Hence hast thou for a little while been subjected to this great affliction. O king, neither Arjuna, nor Bhima, nor any of those foremost of men, viz., the twins, nor Karna, ever truthful in speech and possessed of great courage, could be deserving of Hell for a long time. The princess Krishna too, O Yudhishthira, could not be deserving of that place of sinners.