Matsya Purana — Procedure for Going to Prayaga and the Greatness of the Ganga
षष्टिवर्षसहस्राणि षष्टिवर्षशतानि च सेव्यते पितृभिः सार्धं स्वर्गलोके नराधिप //
ṣaṣṭivarṣasahasrāṇi ṣaṣṭivarṣaśatāni ca sevyate pitṛbhiḥ sārdhaṃ svargaloke narādhipa //
O king, in the heavenly world he is attended and honored together with the Pitṛs for sixty thousand years and a further six hundred years.
This verse does not address Pralaya; it states the duration of heavenly honor gained through merit connected with the Pitṛs (ancestral rites).
By addressing “O king,” the text frames ancestral service (Śrāddha/tarpaṇa) as a core dharma for rulers and householders, promising long-lasting Svarga association with the Pitṛs as its fruit.
The significance is ritual rather than architectural: it highlights the measurable merit (Svarga duration) resulting from proper Pitṛ-related rites such as Śrāddha and offerings to ancestors.