Matsya Purana — Yayati and Indra: Counsel on Forbearance and Right Speech
अरुन्तुदं पुरुषं तीव्रवाचं वाक्कण्टकैर् वितुदन्तं मनुष्यान् विद्याद् अलक्ष्मीकतमं जनानां मुखे निबद्धं निरृतिं वहन्तम् //
aruntudaṃ puruṣaṃ tīvravācaṃ vākkaṇṭakair vitudantaṃ manuṣyān vidyād alakṣmīkatamaṃ janānāṃ mukhe nibaddhaṃ nirṛtiṃ vahantam //
Know that man—who is harsh of speech, who pierces people with thorn-like words—as the most inauspicious among men, bearing ruin (Nirṛti) bound upon his very mouth.
It does not describe cosmic Pralaya; it uses Nirṛti as a moral force of ruin—misfortune that follows harmful speech—showing how ethical decay brings destruction into human life.
It frames harsh, wounding speech as a prime cause of inauspiciousness; for kings and householders, disciplined, non-injurious speech is a core dharma because words can protect society or destabilize it.
No Vāstu or ritual procedure is taught in this verse; the practical takeaway is ethical—speech itself is treated as a power that can invite or repel misfortune.