Matsya Purana — Glory of Prayaga: The Fruit of the Anashaka Fast and the Merit of the Yamuna
कुलानि तारयेद्राजन् दश पूर्वान्दशापरान् मुच्यते सर्वपापेभ्यो गच्छेत्तु परमं पदम् //
kulāni tārayedrājan daśa pūrvāndaśāparān mucyate sarvapāpebhyo gacchettu paramaṃ padam //
O King, he uplifts his lineage—ten generations before and ten generations after. He is freed from all sins and indeed attains the supreme abode.
This verse does not discuss Pralaya; it emphasizes moral causality—righteous merit can spiritually uplift one’s lineage and lead the doer toward the supreme state.
Addressed to a king, it frames dharmic conduct (often including charity, protection of subjects, and ritual duty in this section) as benefiting not only the ruler personally but also ancestors and descendants—linking governance and household merit to lineage welfare.
No direct Vastu or temple-architecture rule is stated here; the verse broadly supports the ritual-ethical idea that dharmic acts generate merit capable of benefiting multiple generations.