Matsya Purana — Glory of Tīrtha-Śrāddha: Best Times
एष्टव्या बहवः पुत्रा यद्येको ऽपि गयां व्रजेत् यजेत वाश्वमेधेन नीलं वा वृषमुत्सृजेत् //
eṣṭavyā bahavaḥ putrā yadyeko 'pi gayāṃ vrajet yajeta vāśvamedhena nīlaṃ vā vṛṣamutsṛjet //
Many sons are to be desired—for if even one of them should go to Gayā, or perform an Aśvamedha sacrifice, or set free a blue-hued bull, that itself brings great merit.
This verse is not about Pralaya; it emphasizes Pitṛ-dharma—merit-producing acts like Gayā pilgrimage, Aśvamedha, and vṛṣotsarga that support ancestral welfare.
It frames a householder’s (and by extension a king’s) duty to sustain lineage and perform dharmic acts: ensuring at least one capable son who can undertake high-merit rites such as Gayā pilgrimage or major yajñas, thereby honoring ancestors and social order.
The significance is ritual rather than architectural: it highlights three high-merit rites—Gayā pilgrimage (often linked with śrāddha), Aśvamedha (royal yajña), and releasing a bull (vṛṣotsarga) as a dharmic act connected to ancestral benefit.