Matsya Purana — Origin of Soma
यस्मादुमापतिः सार्धम् उमया तमधिष्ठितः तं दृष्ट्वा चाष्टमांशेन तस्मात्सोमो ऽभवच्छिशुः //
yasmādumāpatiḥ sārdham umayā tamadhiṣṭhitaḥ taṃ dṛṣṭvā cāṣṭamāṃśena tasmātsomo 'bhavacchiśuḥ //
Because Umāpati (Śiva), together with Umā, had entered into him and presided there, upon beholding that divine presence Soma came forth from him as a child, endowed with an eighth part of that power.
This verse is not about Pralaya; it explains a deity-origin motif—Soma’s manifestation as a child through the presiding presence of Śiva with Umā, emphasizing divine agency in creation rather than cosmic dissolution.
Indirectly, it supports the Purāṇic worldview that legitimate lineage and authority arise from sacred order; kingship and household life are to be aligned with dharma and reverence for the divine sources of dynasties and cosmic functions (like the Moon’s role in time and ritual calendars).
No Vāstu or temple-building rule is stated here; the ritual takeaway is Soma’s divine status, relevant to Soma/Chandra-related observances and calendrical timing in rites where the Moon’s phases guide vrata and yajña schedules.