Mahabharata 12.306.26

12.306.26

kimatra brahmaṇyamṛtaṃ kiṃ ca vedyamanuttamam |
cintaye tatra cāgatya gandharvo māmapṛcchata || 26 ||

'I had thus got from Surya the five times ten Yajushes, O monarch. I then studied the Puranas with Romaharshan. Keeping before me those (original) Mantras and the goddess Saraswati I, then, O king, aided by the inspiration of Surya, set myself to compile the excellent Satapatha Brahmanas, and succeeded in achieving the task never before undertaken by any one else. That path which I had desired to take has been taken by me and I have also taught it to my disciples. Indeed, the whole of those Vedas with their abstracts have been imparted by me to those disciples of mine. Pure in mind and body, all those disciples have, in consequence of my instructions, become filled with joy. Having established (for the use of others) this knowledge consisting of fifty branches which I had obtained from Surya, I now meditate on the great object of that knowledge viz., (Brahma). The Gandharva Viswavasu, well-conversant with the Vedanta scriptures, desirous, O king, of ascertaining what is beneficial for the Brahmanas in this knowledge and what truth occurs in it, and what is the excellent object of this knowledge, one questioned me. He put to me altogether four and twenty questions, O king, relating to the Vedas. Finally, he asked me a question, numbered twenty-fifth which relates to that branch of knowledge which is concerned with the inferences of ratiocination. Those questions are as follows: What is universe and what is not-universe? What is Aswa and what Aswa? What is Mitra?