Vyasa Arrives and Teaches the Pratismriti
While Yudhishthira and Bhimasena are locked in conversation, Vyasa appears — having perceived Yudhishthira's hidden fear about the Kuru warriors. He promises to show how Bhishma, Drona, and the others can be legitimately killed, then teaches Yudhishthira the secret knowledge called pratismriti and tells him that Arjuna must go to the gods for weapons.
The two Pandavas were still conversing when Vyasa arrived — Satyavati's son, the great yogi, the one who saw what others could not. He had perceived, with his insight, what was passing through Yudhishthira's heart, and he had come swiftly.
The Pandavas worshipped him as was due. Then Vyasa, supreme among eloquent speakers, spoke directly to Yudhishthira.
"O Yudhishthira, mighty-armed one, bull among men. I have come because I know what is in your heart. I will dispel the fear that lives there — the fear about Bhishma, Drona, Kripa, Karna, and Drona's son. I will tell you how they can be legitimately killed, according to the rules. Hear this, regain your composure, and do what needs to be done."
Then Parashara's son spoke to Yudhishthira alone. The words were grave and heavy with import.
"The time for you to regain your fortune will come, O supreme one of the Bharata lineage. Partha Dhananjaya will overcome the enemies in battle. Accept from me this knowledge — it is called pratismriti. I will recount it to you. It is success personified. When you have received it, the mighty-armed Arjuna will be successful. For the sake of weapons, he must go to the great Indra, to Rudra, to Varuna, to the lord of riches, and to Dharmaraja. Because of his austerities and valour, he has the power to see the gods. He is an immensely energetic rishi. He is the ancient, eternal, and everlasting god — Narayana's companion, a part of Vishnu himself. When he has obtained weapons from Indra, Rudra, and the Lokapalas (the guardians of the directions), the mighty-armed one will perform great deeds."
Then Vyasa gave Yudhishthira practical counsel: "Think about leaving this forest and going to another that is more appropriate for your residence. It is never pleasant to live in the same place for a long time. It can cause anxiety to the serene ascetics. And since you support many brahmanas learned in the Vedas and the vedangas, the deer will be exhausted and the plants and herbs will decay."
Having spoken, the illustrious lord — Satyavati's intelligent son, learned in yoga — taught Dharmaraja Yudhishthira, who had purified himself, that supreme knowledge of yoga. Then he took Kounteya's leave and instantly disappeared. Aranyaka Parva, Chapter 334