Matsya Purana — Measures of Time: Caturyuga Computation
सत्यं जपस्तपो दानं पूर्वधर्मो य उच्यते यदा धर्मस्य ह्रसते शाखाधर्मस्य वर्धते //
satyaṃ japastapo dānaṃ pūrvadharmo ya ucyate yadā dharmasya hrasate śākhādharmasya vardhate //
Truthfulness, sacred recitation (japa), austerity (tapas), and charity (dāna)—these are declared to be the ancient, foundational Dharma. When that Dharma declines, the branch-like, sectarian forms of Dharma increase.
It does not describe Pralaya directly; it describes moral decline—when core Dharma weakens, derivative or branch practices proliferate.
It prioritizes universal duties—truthfulness, disciplined worship/recitation, self-restraint, and charity—implying that rulers and householders should uphold these core virtues rather than relying only on narrower, factional observances.
No Vastu or temple-architecture rule is stated; the ritual takeaway is that japa (sacred recitation) and dāna (charitable giving) are central, enduring pillars of practice.