Mbh 12.340.4g

As regards Vali, that foremost of Danavas, who is to be unslayable by all the deities, I shall cause him to dwell in the nether regions. In the Treta age I shall take birth as Rama in the race of Bhrigu, and exterminate the Kshatriyas who will become proud of their strength and possessions. Towards the close of Treta and the beginning of Dwapara, I shall take birth as Rama, the son of Dasaratha in Iskshaku's royal line. At that time, the two Rishis viz., the two sons of Prajapati, called by the names of Ekata and Dwita, will in consequence of the injury done by them unto their brother Trita, have to take birth as apes, losing the beauty of the human form. Those apes that shall take birth in the race of Ekata and Dwita, shall become endued with great strength and mighty energy and will equal Sakra himself in prowess. All those apes, O regenerate one, will become my allies for accomplishing the business of the deities. I shall then slay the terrible lord of the Rakshasas, that wretch of Pulastya's race, viz., the fierce Ravana, that throne of all the worlds, together with all his children and followers. Towards the close of the Dwapara and beginning of the Kali ages, I shall again appear in the world taking birth in the city of Mathura for the purpose of slaying Kansa. There, after slaying innumerable Danavas that will be thorns in the side of the deities, I shall take up my residence in Kusasthali at the city of Dwaraka. While residing in that city I shall slay the Asura Naraka, the son of the Earth,--him, that is, who will do an injury to Aditi, as also some other Danavas of the names of Muru and Pitha. Slaying also another foremost of Danavas, viz., the lord of Pragjyotisha, I shall transplant his delightful city furnished with diverse kinds of wealth into Dwaraka. I shall then subjugate the two gods worshipped of all the deities, viz.