Matsya Purana — The Aśūnyaśayana Vrata
न पुत्रपशुरत्नानि क्षयं यान्ति पितामह सप्त कल्पसहस्राणि सप्त कल्पशतानि च कुर्वन्नशून्यशयनं विष्णुलोके महीयते //
na putrapaśuratnāni kṣayaṃ yānti pitāmaha sapta kalpasahasrāṇi sapta kalpaśatāni ca kurvannaśūnyaśayanaṃ viṣṇuloke mahīyate //
O Grandsire, neither sons, nor cattle, nor jewels go to ruin. By performing Aśūnyaśayana—making the bed not empty, that is, offering a bed to a worthy person—one is honored in Viṣṇu’s world for seven thousand kalpas and also seven hundred kalpas.
This verse does not address pralaya; it focuses on dharmic merit (puṇya) from charity—specifically śayyā-dāna—and its long-lasting heavenly reward.
It supports the gṛhastha/royal duty of dāna (charitable giving): donating a bed to a worthy recipient is praised as sustaining prosperity (sons, cattle, wealth) and granting exaltation in Vishnu’s realm.
The ritual point is śayyā-dāna (“making the bed not empty”), a formal gift-item in dāna lists; it is not a Vastu or temple-construction rule, but a prescribed charitable act with stated spiritual results.