Explaining the reason why Narmada had to descend down to earth, Sutji narrated a tale to the assembled sages– ‘Once, Sage Markandeya was taking rest at the bank of river Narmada where Yudhisthira accompanied by Draupadi arrived there. Yudhisthira curiously asked Markandeya about the reason he had chosen the bank of Narmada as his resting place when there were so many other holy places of greater significance. Sage Markandeya recounted a tale, which said how some sages had requested king Pururva to bring down river Narmada to the earth so that the whole world becomes liberated from its sins. Describing the holiness of Narmada, sages had told Pururava- ‘ The holy Narmada is capable of liberating the whole world from its sin. So, you should find means so that Narmada descends down to earth.’ Later on, Pururva did an austere penance to please Shiva. When Lord Shiva appeared before him, Pururva expressed his wish. Shiva instructed Narmada to descend down to earth but she told him that she needed a base for that to happen. Lord Shiva then instructed Paryank- the son of Vindhyachal mountain to hold Narmada while she descended down to earth. Prayank agreed to do that and this was how Narmada came down on earth. Initially, the whole world was flooded with the waters of Narmada but at the request of the deities she minimized her size. Narmada blessed Pururva and instructed him to perform the rituals of tarpan in the name of his ancestors so that they became liberated from their sins. Pururva complied and thus by performing tarpan liberated all his ancestors.’
Having finished his tale, Markandeya told Yudhisthira that one who takes a holy dip in Narmada attains virtues similar to that of performing Ashwamedh yagya.