Matsya Purana — Inquiry into Taraka’s Slaying and the Prelude to Guha
एवमस्त्विति तं देवो जगाम स्वकमालयम् वज्राङ्गो ऽपि समाप्ते तु तपसि स्थिरसंयमः //
evamastviti taṃ devo jagāma svakamālayam vajrāṅgo 'pi samāpte tu tapasi sthirasaṃyamaḥ //
“So be it,” said the god, and departed to his own abode. Vajrāṅga too—his austerity completed—remained steadfast, firm in self-restraint.
This verse does not discuss Pralaya; it marks the closure of an austerity episode—granting assent (“so be it”) and the deity’s return—highlighting disciplined completion rather than cosmic dissolution.
It underscores saṃyama (self-restraint) and steadiness after achieving a goal—an ethical ideal for kings and householders alike: success should culminate in sustained discipline, not indulgence.
No explicit Vāstu/temple rule appears here; the ritual takeaway is the ideal completion of tapas with unwavering restraint, a common Purāṇic standard for efficacy of vows and observances.