Matsya Purana — Measures of Time: Caturyuga Computation
त्रिंशद्यानि तु वर्षाणि दिव्यो मासस्तु स स्मृतः मानुषाणां शतं यच्च दिव्या मासास्त्रयस्तु वै तथैव सह संख्यातो दिव्य एष विधिः स्मृतः //
triṃśadyāni tu varṣāṇi divyo māsastu sa smṛtaḥ mānuṣāṇāṃ śataṃ yacca divyā māsāstrayastu vai tathaiva saha saṃkhyāto divya eṣa vidhiḥ smṛtaḥ //
Thirty human years are remembered as constituting one divine month. Likewise, one hundred human years amount to three divine months. In this way, this traditional method of reckoning “divine time” is preserved.
It gives the technical framework of cosmic time-reckoning used to state vast cycles (yugas, manvantaras) that culminate in periodic dissolutions (pralayas), though this verse itself is specifically about converting human years into divine months.
By clarifying long-cycle chronology, it supports Purāṇic ethics that place dharma within time—helping kings and householders understand the scale of ages (yugas) and the urgency of righteous conduct in a limited human lifespan.
No direct Vāstu or temple-rule is stated here; its ritual value is indirect—time conversion is foundational for calendrical planning and for understanding Purāṇic durations cited in rites, vows, and cosmological narratives.