Matsya Purana — Lineage of the Pitṛs
दशानां त्वं च भविता पितॄणामेकपुत्रकः क्षत्रियत्वे ऽश्वमेधे च रुद्रात्त्वं नाशमेष्यसि //
daśānāṃ tvaṃ ca bhavitā pitṝṇāmekaputrakaḥ kṣatriyatve 'śvamedhe ca rudrāttvaṃ nāśameṣyasi //
You will become the sole son for ten forefathers; established in the Kshatriya estate and through the Aśvamedha sacrifice, by Rudra’s grace you will not meet with destruction.
This verse does not discuss Pralaya directly; it focuses on lineage continuity and divine protection from ruin, a theme often contrasted with cosmic dissolution narratives elsewhere in the Matsya Purana.
It links stable kingship (kṣatriyatva) with Vedic royal duty, especially the Aśvamedha, implying that righteous rule and sanctioned sacrifice uphold social order and protect a ruler from downfall.
The ritual point is the Aśvamedha, a high royal yajña associated with sovereignty and legitimacy; no Vastu or temple-architecture rule is referenced in this specific verse.