Srimad Bhagavatam Canto 11, Chapter 17, Text 11

SB 11.17.11

vedah pranava evagre
 dharmo ’ham vrsa-rupa-dhrk
upasate tapo-nistha
 hamsam mam mukta-kilbisah
In Satya-yuga the undivided Veda is expressed by the syllable om, and I am the only object of mental activities. I become manifest as the four-legged bull of religion, and thus the inhabitants of Satya-yuga, fixed in austerity and free from all sins, worship Me as Lord Hamsa.
The bull of religion is described in Srimad-Bhagavatam (1.17.24): tapah saucam daya satyam iti padah krte krtah. “In the age of Satya [truthfulness], your four legs were established by the four principles of austerity, cleanliness, mercy and truthfulness.” Sri Vyasadeva divided the one Veda into four — the Rg, Yajur, Sama and Atharva Vedas — at the end of Dvapara-yuga, but in Satya-yuga the whole of Vedic knowledge is easily understood by everyone simply by vibrating the syllable om. In this age there are no ritualistic or pious activities such as sacrifice, since everyone is sinless, austere and fully engaged in worshiping the Personality of Godhead, Lord Hamsa, through the process of meditation.
Srimad Bhagavatam Canto 11, Chapter 17, Text 10
Srimad Bhagavatam Canto 11, Chapter 17, Text 12