Mbh 12.309.3a

"'Bhishma continued, "I have thus told thee of high Brahma agreeably to what the great Rishi (Vasishtha) had said (unto king Karala of Janaka's race), by attaining to which the Twenty-fifth (or Jiva) has never to return. Jiva, in consequence of his not knowing truly the Supreme Soul which is not subject to decay and death, is obliged to frequently come back into the world. When, however, Jiva succeeds in acquiring that high knowledge, he has no longer to come back. Having heard it, O king, from the celestial Rishi, I have, O son, communicated to thee high knowledge productive of the highest good. This knowledge was obtained from Hiranyagarbha by the high-souled Rishi Vasishtha. From that foremost of Rishis, viz., Vasishtha, it was acquired by Narada. From Narada I have acquired that knowledge which is truly identifiable with the eternal Brahma. Having heard this discourse of high import, fraught with excellent words, do not, O foremost of the Kurus, yield any longer to grief. That man who knows Kshara and Akshara becomes freed from fear. He, indeed, O king, is obliged to cherish fear who is destitute of this knowledge. In consequence of Ignorance (of Brahma), the man of foolish soul hath repeatedly to come back into this world. Indeed, departing from this life, he has to be born in thousands and thousands of orders of Being every one of which hath death in the end. Now in the world of the deities, now among men, and now among intermediate orders of Being, he has to appear again and again. If in course of time he succeeds in crossing that Ocean of Ignorance in which he is sunk, he then succeeds in avoiding rebirth altogether and attaining to identity with the Supreme Soul. The Ocean of Ignorance is terrible. It is bottomless and called the Unmanifest. O Bharata, day after day, creatures are seen to fall and sink in that Ocean.