Matsya Purana — Code of Conduct and Vow-Procedure for Courtesans
यथान्तरं न पश्यामि कामकेशवयोः सदा तथैव सर्वकामाप्तिर् अस्तु विष्णो सदा मम //
yathāntaraṃ na paśyāmi kāmakeśavayoḥ sadā tathaiva sarvakāmāptir astu viṣṇo sadā mama //
As I never perceive any difference at all between Kāma and Keśava, so too, O Viṣṇu, may the fulfillment of all my desires ever be mine.
This verse does not discuss pralaya directly; it is a devotional statement that emphasizes non-difference in divine forms and seeks the boon of “sarvakāmāpti” (fulfillment of aims).
It supports the ethical ideal of single-minded devotion and right vision (seeing no divisive difference in the divine), which a king/householder can apply as inner discipline while pursuing legitimate aims (kāmas) in a dharmic way.
No Vāstu or temple-construction rule is stated here; the ritual takeaway is the stotra-principle that sincere praise grounded in correct theological understanding is believed to yield desired spiritual and worldly fruits.