Matsya Purana — Characteristics of Dvāpara and Kali Yugas
द्वापरे व्याकुलो भूत्वा प्रणश्यति कलौ पुनः वर्णानां द्वापरे धर्माः संकीर्यन्ते तथाश्रमाः //
dvāpare vyākulo bhūtvā praṇaśyati kalau punaḥ varṇānāṃ dvāpare dharmāḥ saṃkīryante tathāśramāḥ //
In the Dvāpara Yuga, (dharma) becomes disturbed and confused, and in the Kali Yuga it again falls into ruin. In Dvāpara itself, the duties of the social classes (varṇas) become mixed, and likewise the disciplines of the life-stages (āśramas) become intermixed.
This verse is not about cosmic pralaya; it describes a moral and social decline across yugas—confusion in Dvāpara and deeper collapse in Kali—especially in varṇa and āśrama duties.
It implies that rulers and householders must actively preserve clear varṇa-āśrama responsibilities—protecting ethical conduct, proper training, and social discipline—because yuga conditions tend toward confusion and mixing of duties.
No specific Vāstu or temple rule is stated; the ritual takeaway is general: as yugas decline, maintaining correct dharmic procedure and role-based discipline becomes harder and therefore more essential.