Matsyapurana 144.11

144.11

vedaścaikaścaturdhā tu vyasyate dvāparādiṣu
ṛṣiputraiḥ punarvedā bhidyante dṛṣṭivibhramaiḥ //

Before, there was only one Veda, having four feet (parts) That got changed on and on, due to the short lives of the people, until at last in Dvâpara the one Veda was abridged and completely divided in four Vedas The sons of Risis, again due to their respective faulty understandings explained them in various ways They inserted Brahmana portions within the Samhitâ portions of Rik, Yajuḥ and Sama Vedas They even changed the Svaras or musical tones in the songs of the Vedas They did not fully grasp the meanings partly owing to their habits and faulty understandings and partly owing to many corruptions and interpolations in the Vedas, of the Brāhmaṇa portions, of the Kalpa Sûtras of the Bhasyas and of various other things Some parts were correctly explained It is in this Dvaparayuga that persons adopted various customs and rites and began to hold different opinions—10-14