Matsya Purana — Sādhāraṇa Śrāddha: General Ancestral Rite
पानीयमप्यत्र तिलैर्विमिश्रं दद्यात्पितृभ्यः प्रयतो मनुष्यः श्राद्धं कृतं तेन समाः सहस्रं रहस्यमेतत्पितरो वदन्ति //
pānīyamapyatra tilairvimiśraṃ dadyātpitṛbhyaḥ prayato manuṣyaḥ śrāddhaṃ kṛtaṃ tena samāḥ sahasraṃ rahasyametatpitaro vadanti //
Here, even water mixed with sesame seeds should be offered—by a disciplined person—to the Ancestors (Pitṛs). By that act, a śrāddha is as though performed for a thousand years; this is a secret teaching, say the Pitṛs.
This verse does not address pralaya; it focuses on pitṛ-related ritual merit, emphasizing that even a simple sesame-water offering can yield immense spiritual fruit.
It highlights gṛhastha-dharma (and by extension rāja-dharma) through regular honoring of ancestors: a disciplined person should perform pitṛ-offerings, and even minimal resources (water with sesame) suffice when offered with purity and intent.
The ritual takeaway is the primacy of tila-mixed water in pitṛ-tarpaṇa/śrāddha contexts, presented as a potent substitute or enhancement—so effective that it is praised as equal to a thousand years of śrāddha.