Matsya Purana — Ravi-Saṅkrānti Vow: Udyāpana
यावन्महेन्द्रप्रमुखैर्नगेन्द्रैः पृथ्वा च सप्ताब्धियुतेह तिष्ठेत् तावत्स गन्धर्वगणैर् अशेषैः सम्पूज्यते नारद नाकपृष्ठे //
yāvanmahendrapramukhairnagendraiḥ pṛthvā ca saptābdhiyuteha tiṣṭhet tāvatsa gandharvagaṇair aśeṣaiḥ sampūjyate nārada nākapṛṣṭhe //
So long as this earth—together with the seven oceans—endures, and so long as the great mountains headed by Mahendra remain, for that entire span, O Nārada, he is continually honored in the heavenly realm by all the hosts of Gandharvas.
It does not describe Pralaya directly; instead, it uses cosmic stability markers (earth with seven oceans and enduring mountains) as a poetic measure for how long a meritorious person receives honor in Svarga.
The verse functions as a phala-śruti (results statement): it motivates dharmic conduct—charity, vows, worship, and righteous duties—by promising enduring celestial recognition for the doer of the previously stated merit.
No explicit Vāstu/temple-building rule appears in this śloka; its ritual import is the idea of sampūjā (full honor/worship) in heaven as the reward for a specified religious act described in the surrounding passage.