Matsya Purana — Śrāddha Procedure: Types
वैश्वदेवं ततः कुर्यान् निवृत्ते पितृकर्मणि इष्टैः सह ततः शान्तो भुञ्जीत पितृसेवितम् //
vaiśvadevaṃ tataḥ kuryān nivṛtte pitṛkarmaṇi iṣṭaiḥ saha tataḥ śānto bhuñjīta pitṛsevitam //
When the rite for the Ancestors (pitṛ-karman) has been completed, one should then perform the Vaiśvadeva offering. Thereafter, being composed, one should eat together with one’s dear ones the food that has been offered in service to the Pitṛs.
This verse does not address pralaya or cosmology; it focuses on ritual discipline—specifically the proper sequencing of ancestral rites and the Vaiśvadeva offering in daily dharma.
It outlines gṛhastha-ācāra: after completing pitṛ-karman (Śrāddha-related duty), one should perform Vaiśvadeva and then eat calmly with family/esteemed persons, showing that household life is regulated by ordered offerings and self-control.
The significance is ritual (not architectural): it prescribes the order—Pitṛ-karman first, then Vaiśvadeva, then the composed consumption of food associated with the ancestral offering.