Mahabharata Anushasna Parva Chapter 103:4

Mahabharata Anushasna Parva (Dana Dharma Parva) Chapter 103:4 I adored them in a thousand and twenty-eight Viswajit sacrifices. It is not through the merits of those sacrifices O Lord of all the deities, that I have attained to this region. On the banks of Sarayu and Vahuda and Ganga as also in the woods of Naimisha, I gave away millions of kine unto the Brahmanas. It is not through the merits of those acts that I have attained to this region. The vow of fast had been known to Indra. He had, however, kept it a secret. Sukra, the descendant of Bhrigu, obtained a knowledge of it by means of spiritual sight acquired through penances. Blazing with energy as he does, it is Usanas who first made it known to the universe. I observed that vow, O boon giving Deity! When I accomplished that very superior vow, the Brahmanas became all gratified with me. A thousand Rishis came thither. All those Brahmanas and Rishis, O puissant lord, gratified with me, said, "Do thou repair to the region of Brahman!" It is in consequence of the merits of that vow that I have succeeded in attaining to this region of very superior felicity. There is no doubt in this. Asked by the Supreme Ordainer of all things, I have duly expounded the merits of the vow of fast. In my opinion, there is no penance higher than fast. I vow to thee, O foremost of all the deities! Be thou propitious unto me!'" "'Bhishma continued, "King Bhagiratha, who had said so and who deserved every honour was on the conclusion of his speech, honoured by Brahman according to the rites ordained for that purpose. Do thou, therefore, O Yudhishthira, observe the vow of fast and worship the Brahmanas every day. The words uttered by Brahmanas can accomplish everything both here and hereafter. Indeed, the Brahmanas should ever be gratified with gifts of robes, food and white complexioned kine and good dwelling houses and mansions. The very deities should gratify the Brahmanas. Freeing thyself from cupidity, do thou practise this vow of very superior merit that is not known to all!