Matsya Purana — Yayāti and the Kings’ Dialogue on Heavenly Worlds
सत्येन मे द्यौश्च वसुंधरा च तथैवाग्निर्ज्वलते मानुषेषु न मे वृथा व्याहृतमेव वाक्यं सत्यं हि सन्तः प्रतिपूजयन्ति //
satyena me dyauśca vasuṃdharā ca tathaivāgnirjvalate mānuṣeṣu na me vṛthā vyāhṛtameva vākyaṃ satyaṃ hi santaḥ pratipūjayanti //
By truth, heaven and earth stand firm for me; by truth, fire too burns among human beings. My spoken word is never uttered in vain—indeed, the virtuous honor and uphold truth.
It does not describe pralaya directly; it presents truth (satya) as a cosmic sustaining principle—heaven, earth, and even fire’s function are framed as grounded in satya.
It elevates truthful speech as a core duty: a ruler or householder should speak reliably and avoid futile or deceptive words, since the righteous community honors and supports satya as the basis of trust and order.
No specific vastu or temple rule is stated; indirectly, it supports ritual integrity—mantras, vows, and declarations in rites are meaningful only when grounded in truthfulness.