Matsya Purana — Dynastic Genealogies: Paurava–Anu Lines
सो ऽशपत्तं ततः क्रुद्ध एवमुक्तो बृहस्पतिः पुत्रं ज्येष्ठस्य वै भ्रातुर् गर्भस्थं भगवानृषिः //
so 'śapattaṃ tataḥ kruddha evamukto bṛhaspatiḥ putraṃ jyeṣṭhasya vai bhrātur garbhasthaṃ bhagavānṛṣiḥ //
Then, angered at being addressed in that manner, the venerable sage Bṛhaspati pronounced a curse—upon the unborn son in the womb of his elder brother.
This verse is not about pralaya; it illustrates karmic causality within a dynastic narrative—how a sage’s anger and curse can shape lineage outcomes.
It underscores the ethical discipline of speech and conduct: disrespectful or improper address toward elders/teachers can invite severe consequences, affecting even family and progeny—an implied warning for householders and rulers alike.
No Vāstu, temple, or ritual procedure is specified in this verse; its significance is narrative and ethical, focusing on the potency of a ṛṣi’s utterance (śāpa).