Matsya Purana — Yayāti–Aṣṭaka Dialogue: Seniority
सुखं हि जन्तुर्यदि वापि दुःखं दैवाधीनं विन्दति नात्मशक्त्या तस्माद्दिष्टं बलवन्मन्यमानो न संज्वरेन्नापि हृष्येत्कदाचित् //
sukhaṃ hi janturyadi vāpi duḥkhaṃ daivādhīnaṃ vindati nātmaśaktyā tasmāddiṣṭaṃ balavanmanyamāno na saṃjvarennāpi hṛṣyetkadācit //
If a creature meets with happiness or with sorrow, it obtains it under the governance of destiny (daiva), not by its own power alone. Therefore, regarding what is ordained (diṣṭa) as the stronger force, one should never burn with grief, nor ever become elated.
It does not describe Pralaya directly; it teaches a general Purāṇic ethic: events like pleasure and pain arise under daiva (ordained order), so one should maintain steadiness of mind amid world-changes, including large cosmic upheavals.
It advises rulers and householders to avoid extremes of despair or triumph. For a king, this supports stable governance—decisions should not be driven by elation at success or grief at setback, but by dharma and measured effort while accepting outcomes as diṣṭa.
No Vāstu or ritual procedure is stated explicitly. Indirectly, it supports the Vāstu-śāstra mindset of disciplined, steady execution—performing prescribed measures without agitation over uncontrollable results.