Matsya Purana — Origin of Soma
अधः सुस्राव नेत्राभ्यां धाम तच्चाम्बुसम्भवम् दीपयन्विश्वमखिलं ज्योत्स्नया सचराचरम् //
adhaḥ susrāva netrābhyāṃ dhāma taccāmbusambhavam dīpayanviśvamakhilaṃ jyotsnayā sacarācaram //
Then, from below, a divine radiance flowed forth from the two eyes—born of the waters—and with its moonlike glow it illuminated the entire universe, all that moves and all that does not.
It uses classic pralaya–sṛṣṭi imagery: from the primordial waters arises a divine light that restores visibility and order, illuminating the whole cosmos (both animate and inanimate).
Indirectly, it presents illumination as a metaphor for dharma: just as divine radiance makes the world orderly and visible, a king or householder is expected to uphold clarity, protection, and moral order in society.
While not giving a direct Vāstu rule, it foregrounds “light” (jyotsnā/dhāma) as auspicious—supporting ritual and temple contexts where illumination (dīpa, jyoti) symbolizes divine presence and the consecration of space.