Matsya Purana — Vrata-Ṣaṣṭhī: The Sixty Sacred Vows
ज्येष्ठे पञ्चतपाः सायं हेमधेनुप्रदो दिवम् यात्यष्टमीचतुर्दश्यो रुद्रव्रतमिदं स्मृतम् //
jyeṣṭhe pañcatapāḥ sāyaṃ hemadhenuprado divam yātyaṣṭamīcaturdaśyo rudravratamidaṃ smṛtam //
In the month of Jyeṣṭha, one who performs the fivefold austerity (pañcatapā) in the evening and donates a golden cow attains heaven. This is remembered as the Rudra-vrata, to be observed on the eighth and the fourteenth lunar days.
This verse does not discuss pralaya; it focuses on vrata-dharma—ritual austerity (pañca-tapa) and donation (hema-dhenu) as merit-bearing acts leading to heaven.
It frames a householder-style dharmic practice: observing aṣṭamī and caturdaśī with austerity and charitable giving. For rulers too, it implies public dharma through dāna (donation) and personal restraint, reinforcing merit and social welfare.
The significance is ritual rather than architectural: performing pañca-tapa (a heat-austerity) in the evening and giving a symbolic high-value gift (golden cow) as part of Rudra-vrata on aṣṭamī and caturdaśī.