Viṣṇu Purāṇa | Book 3 - Chapter 5
Divisions of the Yajur-veda. Story of Yājñyavalkya: forced to give up what he has learned: picked up by others, forming the Taittirīya-Yajus. Yājñyavalkya worships the sun, who communicates to him the Vājasneyī-Yajus.
Of the tree of the Yajur-veda there are twenty-seven branches, which Vaiśampāyana, the pupil of Vyāsa, compiled, and taught to as many disciples.
Amongst these, Yājñyavalkya, the son of Brahmarāta, was distinguished for piety and obedience to his preceptor.
It had been formerly agreed by the Munis, that any one of them who, at a certain time, did not join an assembly held on mount Meru should incur the guilt of killing a Brahman, within a period of seven nights.
Vaiśampāyana alone failed to keep the appointment, and consequently killed, by an accidental kick with his foot, the child of his sister.
He then addressed his scholars, and desired them to perform the penance expiatory of Brāhmiṇicide on his behalf.
Without any hesitation Yājñyavalkya refused, and said:
"How shall I engage in penance with these miserable and inefficient Brahmans?"
On which his Guru, being incensed, commanded him to relinquish all that he had learnt from him:
"You speak contemptuously," he observed, "of these young Brahmans, but of what use is a disciple who disobeys my commands?"
"I spoke," replied Yājñyavalkya, "in perfect faith; but as to what I have read from you, I have had enough: it is no more than this--" (acting as if he would eject it from his stomach); when he brought up the texts of the Yajus in substance stained with blood. He then departed.
The other scholars of Vaiśampāyana, transforming themselves to partridges (Tittiri), picked up the texts which he had disgorged, and which from that circumstance were called Taittirīya;
and the disciples were called the Charaka professors of the Yajus, from Chāraṇa, 'going through' or 'performing' the expiatory rites enjoined by their master.
Yājñyavalkya, who was perfect in ascetic practices, addressed himself strenuously to the sun, being anxious to recover possession of the texts of the Yajus:
"Glory to the sun," he exclaimed, "the gate of liberation, the fountain of bright radiance, the triple source of splendour, as the Rig, the Yajur, and the Sāma Vedas.
Glory to him, who, as fire and the moon, is one with the cause of the universe: to the sun, that is charged with radiant heat, and with the Suṣumnā ray (by which the moon is fed with light):
to him who is one with the notion of time, and all its divisions of hours, minutes, and seconds: to him who is to be meditated upon as the visible form of Viṣṇu, as the impersonation of the mystic Om:
to him who nourishes the troops of the gods, having filled the moon with his rays; who feeds the Pitris with nectar and ambrosia, and who nourishes mankind with rain; who pours down or absorbs the waters in the time of the rains, of cold, and of heat.
Glory to Brahmā, the sun, in the form of the three seasons: he who alone is the dispeller of the darkness of this earth, of which he is the sovereign lord: to the god who is clad in the raiment of purity, adoration!
Glory to the sun, until the rising of which man is incapable of devout acts, and water does not purify, and touched by whose rays the world is fitted for religious rites: to him who is the centre and source of purification.
Glory to Sāvitrī, to Sūrya, to Bhāskara, to Vivaswat, to Āditya, to the first-born of gods or demons. I adore the eye of the universe, borne in a golden car, whose banners scatter ambrosia."
Thus eulogized by Yājñyavalkya, the sun, in the form of a horse, appeared to him, and said, "Demand what you desire."
To which the sage, having prostrated himself before the lord of day, replied:
"Give me knowledge of those texts of the Yajus with which even my preceptor is unacquainted."
Accordingly the sun imparted to him the texts of the Yajus called Ayātayāma (unstudied), which were unknown to Vaiśampāyana: and because these were revealed by the sun in the form of a horse, the Brahmans who study this portion of the Yajus are called Vājis (horses).
Fifteen branches of this school sprang from Kaṇwa and other pupils of Yājñyavalkya.