The Great Epic Mahabharatam :16.
A discourse of Swami Vivekananda on Mahabharata :
(Delivered at the Shakespeare Club, Pasadena, California, February 1, 1900)
After the conclusion of the Kurukshetra War, the great warrior and venerable grandsire, Bhishma, who fought ten days out of the eighteen days' battle, still lay on his deathbed and gave instructions to Yudhishthira on various subjects, such as the duties of the king, the duties of the four castes, the four stages of life, the laws of marriage, the bestowing of gifts, etc., basing them on the teachings of the ancient sages. He explained Sânkhya philosophy and Yoga philosophy and narrated numerous tales and traditions about saints and gods and kings. These teachings occupy nearly one-fourth of the entire work and form an invaluable storehouse of Hindu laws and moral codes. Yudhishthira had in the meantime been crowned king. But the awful bloodshed and extinction of superiors and relatives weighed heavily on his mind; and then, under the advice of Vyasa, he performed the Ashvamedha sacrifice.
After the war, for fifteen years Dhritarashtra dwelt in peace and honour, obeyed by Yudhishthira and his brothers. Then the aged monarch leaving Yudhishthira on the throne, retired to the forest with his devoted wife and Kunti, the mother of the Pandava brothers, to pass his last days in asceticism.
Thirty-six years had now passed since Yudhishthira regained his empire. Then came to him the news that Krishna had left his mortal body. Krishna, the sage, his friend, his prophet, his counsellor, had departed. Arjuna hastened to Dwârâka and came back only to confirm the sad news that Krishna and the Yâdavas were all dead. Then the king and the other brothers, overcome with sorrow, declared that the time for them to go, too, had arrived. So they cast off the burden of royalty, placed Parikshit, the grandson of Arjuna, on the throne, and retired to the Himalayas, on the Great Journey, the Mahâprasthâna. This was a peculiar form of Sannyâsa. It was a custom for old kings to become Sannyasins. In ancient India, when men became very old, they would give up everything. So did the kings. When a man did not want to live any more, then he went towards the Himalayas, without eating or drinking and walked on and on till the body failed. All the time thinking of God, be just marched on till the body gave way.
Then came the gods, the sages, and they told King Yudhishthira that he should go and reach heaven. To go to heaven one has to cross the highest peaks of the Himalayas. Beyond the Himalayas is Mount Meru. On the top of Mount Meru is heaven. None ever went there in this body. There the gods reside. And Yudhishthira was called upon by the gods to go there.