Matsya Purana — Nārāyaṇa as Haṃsa in the Cosmic Ocean: Vedic Yajña-Puruṣa and Mārkaṇḍeya’s Vi...
तथैवैकार्णवजले नीहारेणावृताम्बरे अव्यग्रः क्रीडते लोके सर्वभूतविवर्जिते //
tathaivaikārṇavajale nīhāreṇāvṛtāmbare avyagraḥ krīḍate loke sarvabhūtavivarjite //
So too, when all is a single ocean of waters and the sky is veiled in mist, he remains untroubled, sporting in that world which is devoid of all beings.
It depicts pralaya as an “ekārṇava” (single cosmic ocean) with the sky obscured by mist, where all beings are absent—yet the Supreme remains calm and untouched, freely ‘sporting’ beyond dissolution.
Indirectly, it teaches steadiness: even when conditions collapse or become uncertain, the ideal ruler/householder should cultivate avyagra (unshaken composure) and act without panic—mirroring the divine equanimity described here.
No direct Vastu or ritual rule is stated; however, the verse supplies the cosmological backdrop (pralaya/ekārṇava) often invoked in temple theology—affirming that sacred order and the Supreme principle endure even when the manifest world dissolves.