Mbh 13.106.4f

After the same manner there is no penance that is superior to the observance of fasts. It was by fasts that the deities have succeeded in becoming denizens of heaven. It is by fasts that the Rishis have attained to high success. Viswamitra passed a thousand celestial years, confining himself every day to only one meal, and as the consequence thereof attained to the status of a Brahmana. Chyavana and Jamadagni and Vasishtha and Gautama and Bhrigu--all these great Rishis endued with the virtue of forgiveness, have attained to heaven through observance of fasts. In former days Angiras declared so unto the great Rishis. The man who teaches another the merit of fasts have never to suffer any kind of misery. The ordinances about fasts, in their due order, O son of Kunti, have flowed from the great Rishi Angiras. The man who daily reads these ordinances or hears them read, becomes freed from sins of every kind. Not only is such a person freed from every calamity, but his mind becomes incapable of being touched by any kind of fault. Such a person succeeds in understanding the sounds of all creatures other than human, and acquiring eternal fame, become foremost of his species."'"