Mbh 12.324.2a

"'Bhishma continued, "The Rishis did not make merit depend upon years or decrepitude or wealth or friends. They said that he amongst them was great that studied the Vedas. All this that thou enquirest about has penances for its root. That penance, again, O son of Pandu, rises from the subjugation of the senses. Without doubt, one incurs fault by giving one's senses the reins. It is only by restraining them that one succeeds in earning success. The merit that attaches to a thousand Horse-sacrifices or a hundred Vajapeyas cannot come up to even a sixteenth portion of the merit that arises from Yoga. I shall, on the present occasion, recite to thee the circumstances of Suka's birth, the fruits he won of his penances, and the foremost end he achieved (by his acts), topics that are incapable of being understood by persons of uncleansed soul. Once on a time on the summit of Meru adorned with karnikara flowers, Mahadeva sported, accompanied by the terrible spirits that were his associates. The daughter of the king of mountains, viz., the goddess Parvati, was also there. There at the close vicinity of that summit, the Island-born (Vyasa) underwent extraordinary austerities. O best of the Kurus, devoted to the practices of Yoga, the great ascetic withdrawing himself by Yoga into his own Soul, and engaged in Dharana, practised many austerities for the sake of (obtaining) a son. The prayer he addressed to the great God was,--'O puissant one, let me have a son that will have the puissance of Fire and Earth and Water and Wind and Space.' Engaged in the austerest of penances, the Island-born Rishi begged that of that God who is incapable of being approached by persons of uncleansed souls, (not by words but) by his Yoga-resolution. The puissant Vyasa remained there for a hundred years, subsisting on air alone, engaged in adoring Mahadeva of multifarious form, the lord of Uma.