Matsya Purana — Tārakāsura’s Austerity and Boon; Mobilization for War; Bṛhaspati’s Fourfold P...
आक्रान्ते तु क्रिया युक्ता सतामेतन्महाव्रतम् दुर्जनः सुजनत्वाय कल्पते न कदाचन //
ākrānte tu kriyā yuktā satāmetanmahāvratam durjanaḥ sujanatvāya kalpate na kadācana //
When one is assailed, action is indeed fitting—this is the great vow of the righteous. Yet a wicked person is never fit to become a good man.
This verse is not about Pralaya; it teaches practical dharma—when confronted by aggression, the righteous may take appropriate action rather than remain passive.
It supports rajadharma and household ethics: a king (or householder) should respond decisively to harm and protect order, while recognizing that habitual wrongdoers may not be reliably reformed and may require restraint or punishment.
No Vastu/temple-architecture rule is stated here; the verse focuses on ethical conduct and justified action in the face of attack.