Matsya Purana — The Greatness of Prayaga: Manasa Tirtha
षष्टितीर्थसहस्राणि षष्टिकोट्यस्तथापगाः माघमासे गमिष्यन्ति गङ्गायमुनसंगमम् //
ṣaṣṭitīrthasahasrāṇi ṣaṣṭikoṭyastathāpagāḥ māghamāse gamiṣyanti gaṅgāyamunasaṃgamam //
In the month of Māgha, sixty thousand sacred fords (tīrthas) and likewise sixty crores of rivers will proceed to the confluence of the Gaṅgā and Yamunā.
This verse is not about pralaya; it exalts sacred geography by portraying all tīrthas and rivers as converging (symbolically) at the Gaṅgā–Yamunā Saṅgama during Māgha.
It supports the householder’s dharma of tīrtha-yātrā and seasonal vows: observing Māgha-month pilgrimage and bathing at Prayāga is presented as a high-merit act aligned with righteous living.
Ritually, it highlights Māgha as a prime time for snāna (sacred bathing) and pilgrimage at the Saṅgama; no specific Vāstu or temple-building rule is stated in this verse.