Matsya Purana — Genealogy from Budha to Purūravas and Yayāti; Raji’s war episode; the Paurava...
स्वामी भव त्वमस्माकं संग्रामे नाशय द्विषः ततो विनाशिताः सर्वे ये ऽवध्या वज्रपाणिना //
svāmī bhava tvamasmākaṃ saṃgrāme nāśaya dviṣaḥ tato vināśitāḥ sarve ye 'vadhyā vajrapāṇinā //
“Be our lord and commander; in this battle, destroy our enemies.” Then all those who were beyond the slaying of Vajrapāṇi (Indra) were utterly destroyed.
This verse is not about Pralaya; it is a battle-supplication emphasizing divine leadership and the destruction of formidable foes, even those said to be “unslayable” by Indra.
It reflects the kṣatriya-ideal of seeking rightful leadership and protection in conflict: a king (or protector) must remove threats to order (dharma), including powerful aggressors whom ordinary defenders cannot subdue.
No Vāstu/temple-architecture detail appears here; the ritual takeaway is the Purāṇic pattern of invoking a higher protector/commander before decisive combat.