Matsya Purana — The Tale of Brahmadatta: Past-life Memory
प्रयच्छन्ति सुतान्राज्यं नृणां प्रीताः पितामहाः य इदं पितृमाहात्म्यं ब्रह्मदत्तस्य च द्विजाः //
prayacchanti sutānrājyaṃ nṛṇāṃ prītāḥ pitāmahāḥ ya idaṃ pitṛmāhātmyaṃ brahmadattasya ca dvijāḥ //
Pleased, the Pitṛs (ancestral grandsires) bestow sons and sovereignty upon men. O twice-born sages, this is the proclaimed greatness of the Pitṛs, as taught in the account of Brahmadatta.
Nothing directly about Pralaya is stated here; the verse instead teaches karmic results (phala) of honoring the Pitṛs—ancestral satisfaction leading to worldly blessings like offspring and sovereignty.
It reinforces the householder-kingly duty of Pitṛ-yajña (ancestor rites): by śrāddha, tarpaṇa, and remembrance of Pitṛ-māhātmya, one sustains lineage (sons) and social order (rājya), key aims for both gṛhasthas and rulers.
The significance is ritual rather than architectural: it highlights the efficacy of Pitṛ-related observances (śrāddha/ancestor veneration), presenting them as a means to secure progeny and political stability.