When the light has risen, there is no day, no night, neither existence nor non-existence; Siva (the blessed) alone is there. That is the eternal, the adorable light of Savitri,—and the ancient wisdom proceeded thence.

In plain words: When this inner light rises, there is no day or night, and no being or not-being. Only Shiva, the blessed one, is there. This is the eternal, holy light of Savitri, the sun god, and the ancient wisdom came from it.