Matsya Purana — Yuga Durations
एषा त्रेतायुगगतिर् विचित्रा देवनिर्मिता द्वापरस्य तु या चेष्टा तामपि श्रोतुमर्हसि //
eṣā tretāyugagatir vicitrā devanirmitā dvāparasya tu yā ceṣṭā tāmapi śrotumarhasi //
“Such is the wondrous course of the Tretā Yuga, fashioned by the gods. Now you should also hear about the mode of conduct that belongs to the Dvāpara Yuga.”
It does not describe Pralaya directly; it frames yuga-order as “deva-nirmitā” (divinely ordained), implying cosmic time and moral order are established by higher powers rather than random events.
It signals that dharma and social conduct are yuga-specific; rulers and householders must adjust governance, ritual emphasis, and ethical practice according to the prevailing yuga’s standards as taught in the subsequent verses.
No direct Vāstu/temple rule is stated; the ritual implication is that practices (ceṣṭā) change by yuga, so rites, austerities, and religious observances are presented as period-appropriate in the larger discourse.