Matsya Purana — Characteristics of Dvāpara and Kali Yugas
अतीतानागतानि स्युर् यानि मन्वन्तरेष्विह एते युगस्वभावास्तु मयोक्तास्तु समासतः //
atītānāgatāni syur yāni manvantareṣviha ete yugasvabhāvāstu mayoktāstu samāsataḥ //
Whatever events and patterns belong to past and future Manvantaras—these intrinsic characteristics of the Yugas have been stated by me here in summary.
It frames time as repeating Manvantara-cycles and Yuga-patterns, implying that cosmic phases (including Pralaya intervals) follow recurring, describable structures across past and future cycles.
By highlighting that each Yuga has its own svabhāva (norms and conditions), it supports the Purāṇic idea that dharma-practice and governance should be aligned with the prevailing age—adapting conduct while preserving core righteousness.
No direct Vāstu or ritual rule is stated; the takeaway is methodological: ritual and social prescriptions in the Purāṇa are often organized by Yuga/Manvantara context, and this verse marks a summarized teaching about those age-specific frameworks.