Matsya Purana — Yayāti and the Kings’ Dialogue on Heavenly Worlds
*ययातिरुवाच न त्वं वाचा हृदयेनापि राजन् परीप्समानो मावमंस्था नरेन्द्र तेनानन्ता दिवि लोकाः स्थिता वै विद्युद्रूपाः स्वनवन्तो महान्तः //
*yayātiruvāca na tvaṃ vācā hṛdayenāpi rājan parīpsamāno māvamaṃsthā narendra tenānantā divi lokāḥ sthitā vai vidyudrūpāḥ svanavanto mahāntaḥ //
Yayāti said: “O King—O lord of men—do not, whether in speech or even in your heart, insult me while seeking to test me. For because of that, countless worlds stand established in heaven—vast, resounding, and radiant like lightning.”
This verse does not describe Pralaya directly; it emphasizes moral causality (speech and intent) and links conduct toward a great person to consequences involving heavenly realms.
It warns a ruler against disrespect—externally or internally—especially when ‘testing’ others; restraint in speech, purity of intention, and honoring the worthy are presented as kingly virtues aligned with dharma.
No explicit Vastu or ritual procedure appears; the imagery of “radiant, resounding heavenly worlds” is cosmological and ethical rather than architectural.