सत्ययुग और त्रेतामें वेद, यज्ञ तथा वर्णाश्रम धर्म विशुद्ध रूपमें पालित होते हैं, परंतु द्वापरयुगमें लोगोंकी आयुका हास होनेके कारण ये भी क्षीण होने लगते हैं ।। द्वापरे विप्लवं यान्ति वेदा: कलियुगे तथा । दृश्यन्ते नापि दृश्यन्ते कलेरन्ते पुन: किल,द्वापपर और कलियुगमें वेद प्रायः लुप्त हो जाते हैं। कलियुगके अन्तिम भागमें तो वे कभी कहीं दिखायी देते हैं और कभी दिखायी भी नहीं देते हैं
satyayuge ca tretāyāṃ ca vedā yajñāś ca varṇāśramadharmaś ca viśuddharūpeṇa pālyante; dvāpare tu janānām āyuṣo hrāsakāraṇād etāny api kṣīyante. dvāpare viplavaṃ yānti vedāḥ kaliyuge tathā; dṛśyante nāpi dṛśyante kaler ante punaḥ kila.
Vyāsa explains that in the Satya and Tretā ages the Vedas, sacrificial rites, and the disciplines of social and spiritual order (varṇa and āśrama) are upheld in a pure and intact form. But in the Dvāpara age, as human lifespan declines, these institutions begin to weaken. In Dvāpara—and even more so in Kali—the Vedas fall into disorder and near-disappearance; and toward the very end of Kali, they are said to appear only intermittently, as if visible in some places and times and absent in others. The ethical warning is clear: when human vitality and discipline diminish, the foundations of dharma—learning, ritual responsibility, and ordered life—become fragile and must be consciously protected.
व्यास उवाच
As human capacity (symbolized by lifespan) declines across the yugas, the practical strength of dharma—Vedic learning, sacrificial responsibility, and disciplined social-spiritual life—also declines; therefore these supports of dharma require deliberate safeguarding, especially in later ages.
Vyāsa is describing the yuga-wise condition of religious and ethical institutions: they are pure and stable in Satya and Tretā, begin to weaken in Dvāpara, and become disrupted and intermittently accessible in Kali, with the Vedas appearing only sporadically toward Kali’s end.