Matsya Purana — The Greatness of Prayāga
एवं योगस्य सम्प्राप्तिस्थानं परमदुर्लभम् गच्छन्ति नरकं घोरं ये नराः पापकर्मिणः //
evaṃ yogasya samprāptisthānaṃ paramadurlabham gacchanti narakaṃ ghoraṃ ye narāḥ pāpakarmiṇaḥ //
Thus, the state that leads to the attainment of Yoga is exceedingly hard to obtain; those men who commit sinful deeds go to a terrible hell.
This verse does not discuss Pralaya directly; it focuses on moral causality—rare spiritual attainment through yoga versus the post-death consequence of sinful action (narrowly framed as Naraka).
It reinforces the Matsya Purana’s dharmic ethic: rulers and householders must avoid pāpa (harmful, unrighteous acts) and cultivate disciplines aligned with yoga, since conduct determines one’s spiritual trajectory and afterlife outcome.
No Vāstu/temple-architecture rule is stated here; the verse is a general dharma-yoga warning that ritual or external acts are insufficient if one persists in pāpakarma.