Srimad-Bhagavatam: Canto 11 - Chapter 1 - Verse 12

Sanskrit:

त्रेतामुखे महाभाग प्राणान्मे हृदयात्‍त्रयी ।विद्या प्रादुरभूत्तस्या अहमासं त्रिवृन्मख: ॥ १२ ॥

ITRANS:

tretā-mukhe mahā-bhāgaprāṇān me hṛdayāt trayīvidyā prādurabhūt tasyāaham āsaṁ tri-vṛn makhaḥ

Translation:

O greatly fortunate one, at the beginning of Tretā-yuga Vedic knowledge appeared from My heart, which is the abode of the air of life, in three divisions — as Ṛg, Sāma and Yajur. Then from that knowledge I appeared as threefold sacrifice.

Purport:

In Tretā-yuga, the bull of religion loses one leg, and only seventy-five percent of religious principles are manifested, represented by the three principal Vedas — Ṛg, Sāma and Yajur. The Lord appears in the process of threefold Vedic sacrifice. The three divisions are understood as follows. The hotā priest offers oblations into the fire and chants the Ṛg Veda; the udgātā priest chants the Sāma Veda; and the adhvaryu priest, who arranges the sacrificial ground, altar, etc., chants the Yajur Veda. In Tretā-yuga such sacrifice is the authorized process for spiritual perfection. The word prāṇāt in this verse refers to the universal form of the Personality of Godhead. This form is further described in the following verses.