त्रेतादौ केवला वेदा यज्ञा वर्णाश्रमास्तथा । संरोधादायुषस्त्वेते व्यस्यन्ते द्वापरे युगे
tretādau kevalā vedā yajñā varṇāśramās tathā | saṃrodhād āyuṣas tv ete vyasyante dvāpare yuge ||
Vyāsa said: “In the beginning of the Tretā age, the Vedas alone were in their undivided form, and so too were the sacrificial rites and the system of social classes and life-stages. But as human lifespan becomes constrained, these are arranged and distributed in the Dvāpara age.”
व्यास उवाच
As human capacities—especially lifespan—diminish across the ages, the preservation and practice of dharma adapts: what was once held as a single, integral Vedic and ritual order becomes systematized and divided in the Dvāpara-yuga to remain accessible and workable.
Vyāsa is explaining a yuga-based account of religious and social organization: in early ages the Vedas, sacrifices, and the varṇa–āśrama framework are presented as ‘whole’ or unified, but later—specifically in Dvāpara—these are arranged into divisions in response to the shortening of human life.