Matsya Purana — The Cave-Sanctuary: Jewel-Lake
बिलाद्बहिर्गुहां कांचिद् आश्रित्य सुमनोहराम् तपश्चकार तत्रैव पूजयन्मधुसूदनम् //
bilādbahirguhāṃ kāṃcid āśritya sumanoharām tapaścakāra tatraiva pūjayanmadhusūdanam //
Leaving the mouth of the cavern, he took shelter in a certain exceedingly beautiful cave; there itself he practiced austerities, worshipping Madhusūdana (Viṣṇu), the slayer of Madhu.
This verse does not describe pralaya; it highlights a devotional-ascetic response—taking refuge in a secluded cave and worshipping Viṣṇu—typical of Purāṇic guidance for spiritual steadiness rather than cosmic dissolution.
Even for householders or rulers, the verse models disciplined devotion: setting aside a dedicated place and time for worship (pūjā) and self-restraint (tapas), implying that dharma is strengthened through regular, sincere Viṣṇu-bhakti.
Ritually, it foregrounds pūjā to Madhusūdana performed in a sanctified, secluded space; architecturally it suggests the ideal of a quiet, protected setting (like a cave/guha) for austerity—useful when mapping “Matsya Purana ritual space” themes, though it is not a direct Vāstu rule.