Matsya Purana — Indra Sends Soma to Battle: Frost-Weapon
लोकच्छायामयं लक्ष्म तवाङ्कः शशसंनिभः न विदुः सोम देवापि ये च नक्षत्रयोनयः //
lokacchāyāmayaṃ lakṣma tavāṅkaḥ śaśasaṃnibhaḥ na viduḥ soma devāpi ye ca nakṣatrayonayaḥ //
This mark is formed of the world’s shadow; the emblem upon you is like a hare. Even Soma and the gods—indeed, those born of the lunar mansions (the Nakṣatras)—do not fully know it.
Indirectly, it frames cosmic phenomena as governed by deeper laws: even gods do not fully fathom certain celestial marks, implying the universe’s workings exceed ordinary divine and human knowledge—an outlook consistent with Purāṇic cosmology that also underlies Pralaya narratives.
It supports a dharmic attitude of epistemic humility: rulers and householders should heed traditional astronomical/omenic knowledge (Jyotiṣa) for timing and decision-making, while recognizing that some cosmic signs remain ultimately mysterious.
No direct Vāstu rule is stated, but the verse reinforces the ritual importance of lunar symbolism (Soma/Nakṣatra): such astral markers guide calendrical observances, fasts, and nakṣatra-based muhurta selection used in temple rites and consecrations.