Matsya Purana — Glory of Prayaga: The Fruit of the Anashaka Fast and the Merit of the Yamuna
उपासते स्म संध्यां ये त्रिकालं हि युधिष्ठिर देवाः सेवन्ति तत्तीर्थं ये चान्ये विबुधा जनाः //
upāsate sma saṃdhyāṃ ye trikālaṃ hi yudhiṣṭhira devāḥ sevanti tattīrthaṃ ye cānye vibudhā janāḥ //
O Yudhiṣṭhira, those who worship Sandhyā at the three appointed times—indeed, the gods resort to that tīrtha, and other enlightened beings do so as well.
This verse does not discuss Pralaya; it emphasizes daily ritual discipline (trikāla Sandhyā) and the sanctifying power of a tīrtha that even divine beings honor.
It frames trikāla Sandhyā worship as a core dharma for disciplined life—relevant to householders for daily purity and to kings for personal restraint and legitimacy through adherence to Vedic rites.
The significance is ritual: Sandhyā-vandana performed three times daily and the idea of a tīrtha as a spiritually charged site worthy of regular resort by gods and sages; no Vāstu/temple-construction rule is stated in this verse.