Matsya Purana — Bhīma-Dvādaśī
उपास्य संध्यां विधिवत् कृत्वा च पितृतर्पणम् प्रणम्य च हृषीकेशं सप्तलोकैकमीश्वरम् //
upāsya saṃdhyāṃ vidhivat kṛtvā ca pitṛtarpaṇam praṇamya ca hṛṣīkeśaṃ saptalokaikamīśvaram //
Having duly performed the Sandhyā worship, and having also carried out the libations for the ancestors (pitṛ-tarpaṇa), one should bow to Hṛṣīkeśa—the one sovereign Lord of the seven worlds.
It does not describe Pralaya directly; it affirms Vishnu (Hṛṣīkeśa) as the one Lord over the seven worlds, implying cosmic sovereignty that endures beyond cyclical changes.
It outlines nitya-karma: perform Sandhyā according to injunction and offer pitṛ-tarpaṇa, then conclude with devotion and surrender to Vishnu—presented as a universal duty for disciplined householders and rulers alike.
The significance is ritual (not architectural): it prescribes the proper sequence—Sandhyā rite, ancestor libations, and final obeisance to Hṛṣīkeśa—highlighting orderly procedure (vidhivat) as the essence of orthodox practice.