Matsya Purana — The Glory of Prayaga: Pilgrimage
गङ्गायमुनयोर्मध्ये स्नातो मुच्येत किल्बिषात् मनसा चिन्तयन्कामान् अवाप्नोति सुपुष्कलान् //
gaṅgāyamunayormadhye snāto mucyeta kilbiṣāt manasā cintayankāmān avāpnoti supuṣkalān //
One who bathes in the space between the Gaṅgā and the Yamunā is freed from sin; and by mentally contemplating one’s desired aims, one attains those wishes in abundant measure.
This verse does not discuss pralaya; it focuses on tīrtha-māhātmya—purificatory merit gained through sacred bathing and mental intention.
It supports the householder/kingly dharma of periodic purification and pilgrimage: bathing at renowned tīrthas is presented as a means to remove moral impurity and to pursue legitimate aims through disciplined intention.
The ritual point is snāna (sacred bathing) at the Gaṅgā–Yamunā region; no vāstu/temple-building rule is stated, but the verse underscores tīrtha-based rites for purification and merit.