Matsya Purana — Soma
कर्मस्वेतेषु ये सक्ता वर्तन्त्य् आ देहपातनात् देवैस्ते पितृभिः सार्धम् ऊष्मपैः सोमपैस्तथा स्वर्गता दिवि मोदन्ते पितृमन्त उपासते //
karmasveteṣu ye saktā vartanty ā dehapātanāt devaiste pitṛbhiḥ sārdham ūṣmapaiḥ somapaistathā svargatā divi modante pitṛmanta upāsate //
Those who remain devoted to these prescribed rites and duties, continuing in them until the falling of the body (death), go to heaven; there, together with the gods and the Pitṛs—and with the classes known as the Ūṣmapas and the Somapas—they rejoice in the celestial realm and worship the Pitṛs endowed with power.
This verse is not about Pralaya; it focuses on karma-phala—how steadfast performance of prescribed duties up to death leads to Svarga in the company of Devas and Pitṛs.
It affirms the Matsya Purana’s ethic that sustained commitment to one’s ordained rites (nitya/naimittika karma, including ancestor rites) until life’s end yields auspicious posthumous destiny—an ideal especially relevant to householders and rulers who uphold dharma through ritual and social order.
The ritual emphasis is on continued performance of prescribed karmas and Pitṛ-upāsanā (ancestor veneration, commonly expressed through Śrāddha offerings); no Vāstu or temple-construction rule is stated in this specific verse.