Matsya Purana — Phala-Saptamī Vow
यथा न विफलाः कामास् त्वद्भक्तानां सदा रवे तथानन्तफलावाप्तिर् अस्तु मे सप्तजन्मसु //
yathā na viphalāḥ kāmās tvadbhaktānāṃ sadā rave tathānantaphalāvāptir astu me saptajanmasu //
O Ravi (Sun-god), just as the wishes of your devotees are never fruitless, so too may I attain endless merit and its fruits through seven births.
This verse does not discuss pralaya or cosmology; it focuses on devotional efficacy—how worship of Ravi yields unfailing results and enduring merit across multiple births.
It supports the householder/kingly ethic of sustaining dharma through regular worship: devotion (bhakti) and righteous intent are presented as reliable means to secure welfare and merit not only in this life but across successive births.
No explicit Vastu or temple-building rule appears here; the ritual takeaway is the phala principle—Sun-devotion is portrayed as consistently fruitful, encouraging stotra-japa, pūjā, and vrata-oriented practice aimed at long-term puṇya.