Matsya Purana — Vishnu’s Battle with Mathana
निर्मथ्य पाणिना पाणिं धनुरादाय भैरवम् सज्यं चकार स धनुः शरांश्चाशीविषोपमान् //
nirmathya pāṇinā pāṇiṃ dhanurādāya bhairavam sajyaṃ cakāra sa dhanuḥ śarāṃścāśīviṣopamān //
Clenching one hand with the other, he took up the dreadful Bhairava-bow, strung it, and readied arrows comparable to venomous serpents.
This verse is not about pralaya; it uses martial imagery—stringing a fearsome bow and serpent-like arrows—to depict readiness for conflict.
It aligns with kṣatriya-dharma: disciplined preparation and resolve in confronting threats, symbolized by taking up weapons with controlled strength.
No explicit Vāstu or temple-ritual rule appears here; the key takeaway is the Purāṇic convention of describing weapons with sacred-terror imagery (e.g., “Bhairava,” “poisonous serpent”).