Salutation to the self, by whose light even the sun and the stars appear to shine, though it needs no other light to shine by
The text's closing gesture is an act of reverence rather than an argument, honoring the self as the one light nothing else, not even the sun, actually shines without.
The image of the self as a light that illuminates all other lights has deep roots in earlier Vedantic literature — both the Katha and Mundaka Upanishads describe the atman in strikingly similar terms, as what the sun, moon, and stars all shine only by virtue of, needing no other source of light themselves. The logic is that the sun, stars, and every other source of illumination are only ever known because consciousness is present to know them; take consciousness away and no light, however bright, could be perceived as light at all. Consciousness itself, by contrast, needs nothing external to be known — it's self-luminous, aware of itself without borrowing illumination from anywhere else. Ending the text on a salutation rather than an argument fits its overall arc: the teaching doesn't build to a proof, it builds to a recognition worth bowing to.
The self-luminous image directly parallels the Mundaka and Katha Upanishads, situating the Ashtavakra Gita's conclusion within a much older Vedantic lineage of describing consciousness as light that requires no other light to see by.
Ashtavakra Gita