Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
King Yudhisthira, who was much aggrieved, could not be convinced, despite instructions by great sages headed by Vyasa and the Lord Krsna Himself, the performer of superhuman feats, and despite all historical evidence.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The pious King Yudhisthira was mortified because of the mass massacre of human beings in the Battle of Kuruksetra, especially on his account. Duryodhana was there on the throne, and he was doing well in his administration, and in one sense there was no need of fighting. But on the principle of justice Yudhisthira was to replace him. The whole clique of politics centered around this point, and all the kings and residents of the whole world became involved in this fight between the rival brothers. Lord Krsna was also there on the side of King Yudhisthira. It is said in the Mahabharata, Adi-parva (2.25) that 640,000,000 men were killed in the eighteen days of the Battle of Kuruksetra, and some hundreds of thousands were missing. Practically this was the greatest battle in the world within five thousand years.
This mass killing simply to enthrone Maharaja Yudhisthira was too mortifying, so he tried to be convinced with evidences from histories by great sages like Vyasa and the Lord Himself that the fight was just because the cause was just. But Maharaja Yudhisthira would not be satisfied, even though he was instructed by the greatest personalities of the time. Krsna is designated herein as the performer of superhuman actions, but in this particular instance neither He nor Vyasa could convince King Yudhisthira. Does it mean that He failed to be a superhuman actor? No, certainly not. The interpretation is that the Lord as isvara, or the Supersoul in the hearts of both King Yudhisthira and Vyasa, performed still more superhuman action because the Lord desired it. As Supersoul of King Yudhisthira, He did not allow the King to be convinced by the words of Vyasa and others, including Himself, because He desired that the King hear instructions from the dying Bhismadeva, who was another great devotee of the Lord. The Lord wanted that at the last stage of his material existence the great warrior Bhismadeva see Him personally and see his beloved grandchildren, King Yudhisthira, etc., now situated on the throne, and thus pass away very peacefully. Bhismadeva was not at all satisfied to fight against the Pandavas, who were his beloved fatherless grandchildren. But the ksatriyas are also very stern people, and therefore he was obliged to take the side of Duryodhana because he was maintained at the expense of Duryodhana. Besides this, the Lord also desired that King Yudhisthira be pacified by the words of Bhismadeva so that the world could see that Bhismadeva excelled all in knowledge, including the Lord Himself.