Matsya Purana — Characteristics of Dvāpara and Kali Yugas
अनिश्चयावगमनाद् धर्मतत्त्वं न विद्यते धर्मतत्त्वे ह्यविज्ञाते मतिभेदस्तु जायते //
aniścayāvagamanād dharmatattvaṃ na vidyate dharmatattve hyavijñāte matibhedastu jāyate //
Because Dharma is approached without firm ascertainment, the true principle of Dharma is not known; and when the truth of Dharma remains unknown, differences of opinion inevitably arise.
This verse does not discuss Pralaya directly; it addresses epistemic uncertainty in knowing dharma-tattva and explains that such uncertainty leads to conflicting views.
It cautions rulers and householders that policy and conduct must rest on well-ascertained Dharma; otherwise, indecision and ignorance of dharma-tattva produce factional disputes, inconsistent judgments, and unstable social order.
No specific Vastu or ritual rule is stated; indirectly, it implies that rituals, temple procedures, and Vastu decisions require clear pramāṇa-based determination—otherwise competing opinions will proliferate.