Matsya Purana — Conclusion of the Prayaga Mahatmya: Kingship Restored
दश तीर्थसहस्राणि तिस्रः कोट्यस्तथापगाः माघमासे गमिष्यन्ति गङ्गायां भरतर्षभ //
daśa tīrthasahasrāṇi tisraḥ koṭyastathāpagāḥ māghamāse gamiṣyanti gaṅgāyāṃ bharatarṣabha //
O bull among the Bhāratas, in the month of Māgha, ten thousand tīrthas (sacred fords) and likewise three crores of rivers will make their way to the Gaṅgā.
This verse is not about Pralaya; it expresses a sacred-geographical idea that, during Māgha, the merit (puṇya) of many tīrthas and rivers is believed to be present in Gaṅgā, magnifying the fruit of bathing and pilgrimage.
It supports the dharma of seasonal observances: a householder (and a king guiding public religion) is encouraged to sponsor or undertake Māgha-month vows—especially Gaṅgā bathing and tīrtha practices—seen as accessible means to accrue merit and purify conduct.
Ritually, it highlights Māgha snāna (holy bathing) in the Gaṅgā as exceptionally potent, implying that Gaṅgā-ghāṭs and bathing rites during Māgha carry heightened sanctity; architectural details are not specified in this verse.