KARNA WAS ABOUT TO BECOME THE KING NOT YUDHISHTIR

Lord Krishna asked Karna to triumph over Kauravas and become the king

Brave warrior Karna was once firstborn to Kunti; wife of King Pandu, who was adopted and raised via Suta clan leader Adhiratha and Radha. Lord Krishna had already assured Karna to become the king of the earth only if he would have chosen to join the Pandavas. Here in this publish I will let you know Lord Krishna's discussion with Karna related to this offer and what was his reply. I'm certain few of us are already conscious of Krishna's suggestion towards Karna however there's extra to it. Karna actually knew that he alongside other Kauravas were about to die at the hands of Pandavas in the combat yet he denied the offer. Karna used to be no doubt a spiritual warrior who continually donated to all the Brahmins, sacrificed his Kavach and Kundal to Indra, and then it was enthralling to comprehend that he even sacrificed the throne which he virtually deserved.

At the time of leaving Hastinapura, Karna alongside Sanjay also accompanied Lord Krishna on his chariot. Lord Krishna noted Karna about his birth from his real mother Kunti and Sun-god before Kunti's marriage. Hence he was the elder brother of Pandavas and the rightful heir to the throne. Lord Krishna recommended him to join his brothers, not the Kauravas. 

Krishna additionally guaranteed Karna that, "after understanding the truth about you being born to Kunti, the complete Brishni clan human beings along with other kings will support you as their family member, Your younger brother Pandavas alongside their sons will offer your prayers to you, The family priest of Pandavas Dhaumya will inaugurate you as the king of the earth, Religious Yudhishthira will emerge as Yuvraj and lift the white chambar whilst sitting behind you on his chariot, Bhima will carry white chatra on his head, different clan humans will also serve you."

After listening to this, Karna appreciated Lord Krishna for such an offer. he replied that, "I completely understand the fact of being elder to the Pandavas however in my childhood Kuntidevi already abandoned me in the water where i was not safe even, from where Adhiratha and Radha found and took care of me, and married me off to suta females. I have already regarded Adhiratha and Radha as my parents only, have been attached to suta people, my wives, sons also whom I do not want to turn out to be untrue. I do not wish to disappoint Duryodhana who have begun a fight against Pandavas only after trusting my strength. It will be disgraceful for me no longer to combat with Arjuna too."

Karna requested Krishna to keep this secret to himself only. Karna knew that being pious by way of nature Yudhishthira would in no way accept the throne after knowing about Karna being his elder brother. Karna then regretted giving the rude statements to Pandavas while favoring Duryodhana and also agreed that Pandavas deserved to get back their kingdom Hastinapura after completing fourteen years of exile. Additionally, he also referred to Lord Krishna about the ominous signs and symptoms that he noticed and dreamt about the defeat of the Kauravas, these kings who had supported them, the destruction of many Kshatriyas and about the triumph of Pandavas over Kauravas.

Lord Krishna also confirmed the victory of Pandavas. However, Karna being loyal to Duryodhana didn't accept the offer and choosed to combat in favor of Duryodhana and acquire heaven instead.

Ref: Mahabharata book

You can find out how did Karna declined to obey his mother  kunti in the below post

https://vyasamahabharat2.blogspot.com/2020/11/karna-blamed-his-mother-kunti.html