Matsya Purana — Vrata-Ṣaṣṭhī: The Sixty Sacred Vows
कार्त्तिक्यादितृतीयायां प्राश्य गोमूत्रयावकम् नक्तं चरेदब्दमेकम् अब्दान्ते गोप्रदो भवेत् //
kārttikyāditṛtīyāyāṃ prāśya gomūtrayāvakam naktaṃ caredabdamekam abdānte goprado bhavet //
Beginning from the third lunar day in the month of Kārttika, having partaken of barley prepared with cow’s urine, one should observe the ‘night-only’ regimen for one full year; at the end of the year, one should give a cow in donation.
This verse is not about pralaya; it belongs to the Matsya Purana’s vrata-dharma material, prescribing a year-long austerity and concluding go-dāna.
It frames a disciplined household/royal observance: regulated diet (barley with gomūtra), a nakta regimen for a year, and the dharmic duty of charity—culminating in gifting a cow (go-dāna).
The ritual significance is vrata-practice: timing from Kārttika tṛtīyā, a prescribed austerity (nakta), and the completion rite of go-dāna; no Vāstu or temple-architecture rule is stated in this verse.