Mbh 2.12.2b

Those again that yield up their bodies after severe ascetic penances also attain to the same region and shine brightly there for ages. O king of the Kuru race, O son of Kunti, thy father Pandu, beholding the good fortune of Harischandra and wondering much thereat, hath told thee something. Knowing that I was coming to the world of men, he bowed unto me and said,--Thou shouldst tell Yudhishthira, O Rishi, that he can subjugate the whole Earth inasmuch as his brothers are all obedient to him. And having done this let him commence the grand sacrifice called Rajasuya. He is my son; if he performeth that sacrifice, I may, like Harischandra, soon attain to the region of Indra, and there in his Sabha pass countless years in continuous joy. I told him in reply,--O King, I shall tell thy son all this, if I go to the world of man. I have now told thee what he said, O tiger among men. Accomplish then, O son of Pandu, the desires of thy father. If thou performest that sacrifice, thou shall then be able to go, along with thy deceased ancestors, into the same region that is inhabited by the chief of the immortals. It hath been said,--O king, that the performance of this great sacrifice is attended with many obstacles. A class of Rakshasas called Brahma Rakshasas, employed in obstructing all sacrifices, always search for loop-holes when this great sacrifice is commenced. On the commencement of such a sacrifice a war may take place destroying the Kshatriyas and even furnishing occasion for the destruction of the whole Earth. A slight obstacle may involve the whole Earth in ruin. Reflecting upon all this, O king of kings do what is for thy good. Be thou watchful and ready in protecting the four orders of thy subjects. Grow, thou in prosperity, and enjoy thou felicity. Gratify thou the Brahmanas with gifts of wealth. I have now answered in detail all that thou hast asked me. With thy leave I will now go to the city (Dwaravati) of that Dasarhas.”