Matsya Purana — The Aśūnyaśayana Vrata
लक्ष्म्या न शून्यो वरद शय्यां त्वं शयनं गतः शय्या ममाप्यशून्यास्तु तथैव मधुसूदन //
lakṣmyā na śūnyo varada śayyāṃ tvaṃ śayanaṃ gataḥ śayyā mamāpyaśūnyāstu tathaiva madhusūdana //
O bestower of boons, when You go to rest upon the couch, may it not be empty of Lakṣmī. And may my own couch likewise not be devoid (of You), O Madhusūdana.
It does not directly discuss pralaya; instead, it emphasizes auspicious presence (Śrī/Lakṣmī) with Vishnu, a symbolic assurance of continuity, prosperity, and order rather than dissolution.
It reflects the Purāṇic ideal that prosperity (Lakṣmī) and dharma flourish where harmonious companionship and mutual presence are honored—an implicit ethic for household stability and, by extension, a king’s duty to sustain śrī (welfare and auspicious order) in the realm.
No explicit Vāstu rule is stated, but the imagery of an “unempty couch” functions as an auspicious motif (maṅgala) used in ritual-poetic contexts to signify completeness, prosperity, and the presence of divine grace in domestic space.