Matsya Purana — The Greatness of Prayaga and the Supremacy of Cow-Donation
आर्तानां हि दरिद्राणां निश्चितव्यवसायिनाम् स्थानमुक्तं प्रयागं तु नाख्येयं तु कदाचन //
ārtānāṃ hi daridrāṇāṃ niścitavyavasāyinām sthānamuktaṃ prayāgaṃ tu nākhyeyaṃ tu kadācana //
Indeed, for the afflicted and the poor—those resolute in their undertaking—Prayāga has been declared the sure refuge; yet it should never be divulged casually to anyone.
This verse does not discuss pralaya; it focuses on tīrtha-māhātmya—Prayāga as a spiritual refuge—rather than cosmic creation or dissolution.
It implies a dharmic duty to guide the distressed and poor toward meritorious practices (like pilgrimage), while also preserving sacred knowledge from careless publicity—teaching discernment (viveka) in giving counsel.
No vastu/temple-architecture rule is stated; the ritual takeaway is that Prayāga is a specially efficacious tīrtha for the afflicted and that its praise is to be shared with discretion, not indiscriminately.