Matsya Purana — Purūravas Witnesses the Sports of Apsarases and Gandharvas; Attains the Grace...
स्वप्नमेवं स राजर्षिर् दृष्ट्वा देवेन्द्रविक्रमः प्रत्यूषकाले विधिवत् स्नातः स प्रयतेन्द्रियः //
svapnamevaṃ sa rājarṣir dṛṣṭvā devendravikramaḥ pratyūṣakāle vidhivat snātaḥ sa prayatendriyaḥ //
Having thus seen the dream, that royal sage—mighty like Indra—bathed at the pre-dawn hour according to proper rule, with his senses restrained and disciplined.
This verse does not describe pralaya directly; it highlights dharmic preparedness—purification and restraint—often prescribed before responding to portentous events such as dreams.
It models ideal conduct: after receiving a significant sign (a dream), a ruler should begin with pre-dawn ritual bathing and self-control, acting from purity and discipline rather than impulse.
The ritual point is pratyūṣa-snānā (pre-dawn bath) done vidhivat (per injunction), a standard purity prerequisite before any major rite, consultation, vow, or temple-related activity.