Matsya Purana — Sādhāraṇa Śrāddha: General Ancestral Rite
दर्भासनं तु दत्त्वादौ त्रीणि पात्राणि पूरयेत् खपवित्राणि कृत्वादौ शं नो देवीत्य् अपः क्षिपेत् //
darbhāsanaṃ tu dattvādau trīṇi pātrāṇi pūrayet khapavitrāṇi kṛtvādau śaṃ no devīty apaḥ kṣipet //
First, having placed a seat of darbha grass, one should fill three vessels. Having first purified them by the prescribed act, one should sprinkle water into them while reciting “Śaṃ no devīḥ….”
This verse is not about pralaya; it focuses on preparatory ritual purity—setting a darbha seat, preparing vessels, and sanctifying water with a Vedic mantra.
It reflects the nitya-karma mindset central to Matsya Purana dharma: even householders (and kings as exemplars) should begin worship with orderly preparation, cleanliness, and mantra-based sanctification.
Ritually, it prescribes pātra-śuddhi (purifying vessels) and mantra-sprinkling of water; the darbha seat indicates a standard Vedic-paurāṇic setup for rites before any formal worship or offering.