Matsya Purana — Characteristics of Dvāpara and Kali Yugas
मिथुनानि तु ताः सर्वा ह्य् अन्योन्यं सम्प्रजज्ञिरे ततस्तास्तु म्रियन्ते वै पूर्वोत्पन्नाः प्रजास्तु याः //
mithunāni tu tāḥ sarvā hy anyonyaṃ samprajajñire tatastāstu mriyante vai pūrvotpannāḥ prajāstu yāḥ //
All those beings, forming into pairs, generated offspring with one another; and then, indeed, the earlier-born creatures among them die.
It describes a basic cosmic-law pattern within creation: beings multiply through pairing, and generational turnover follows—earlier-born creatures inevitably die, showing mortality as built into the created order (a prerequisite for cyclical dissolution and renewal).
By emphasizing lineage through procreation and the inevitability of death, it supports the householder’s duty to sustain family and society responsibly (praja/continuity), and reminds rulers to govern with awareness of impermanence—prioritizing dharma and orderly succession over personal permanence.
No direct Vastu or ritual procedure is stated; the takeaway is thematic: temple-building and rites in the Matsya Purana are framed within cosmic order and continuity—human works and lineages persist through succession even as individuals pass away.