Mbh 12.349.6

"Vaisampayana said, 'That which is the twenty-fifth (in the enumeration of topics as made in the Sankhya system) viz., when it becomes able to abstain entirely from acts, succeeds in attaining to the Purushottama which is exceedingly subtile, which is invested with the attribute of Sattwa (in its subtile form), and which is fraught with the essences symbolised by three letters of the alphabet (viz., A, U, and M). The Sankhya system, the Aranyaka-Veda, and the Pancharatra scriptures, are all one and the same and form parts of one whole. Even this is the religion of those that are devoted with their whole souls to Narayana, the religion that has Narayana for its essence.[1909] As waves of the ocean, rising from the ocean, rush away from it only to return to it in the end, even so diverse kinds of knowledge, springing from Narayana, return to Narayana in the end. I have thus explained to thee, O son of Kuru's race, what the religion of Sattwa is. If thou beest competent for it, O Bharata, do thou practise that religion duly. Even thus did the highly-blessed Narada explain to my preceptor,--the Island-born Krishna--the eternal and immutable course, called Ekanta, (ending in One) followed by the Whites[1910] as also by the yellow-robed Yatis. Vyasa gratified with Dharma's son Yudhishthira, imparted this religion to king Yudhishthira the just who was possessed of great intelligence. Derived from my preceptor I have also communicated it to thee! O best of kings, this religion is for these reasons, exceedingly difficult of practice. Others, hearing it, become as much confounded as thou hast suffered thyself to be. It is Krishna who is the protector of the universe and its beguiler. It is He who is the destroyer and the cause, O monarch.'"