गोविन्द भाष्य (श्रील बलदेव विद्याभूषण - अचिन्त्यभेदाभेद वेदान्त ब्रह्मसूत्र भाष्य सटीक)

arcir-ādinā tat prathiteḥ
arciḥ—light; ādinā—beginning with; tat—that; prathiteḥ—because of being
well known.
It begins with light, for that is well known.
Purport by Śrīla Baladeva Vidyābhūṣaṇa
The enlightened souls travels to the world of the Supreme Personality of
Godhead on a path that begins with light. Why is that? The sūtra explains, "tat
prathiteḥ" (for that is well known). In the Chāndogya Upaniṣad (5.10.1) it is said:
tad ya ittham vidur ye ceme 'raṇye śraddhāṁ tapa ity upāsate te arciṣam
"This they know: They who perform austerities and worship the Lord with faith
travel on the path that begins with light."
This passage is taken from the chapter describing the knowledge of the five
fires (pañcāgni-vidyā). Therefore the path that begins with light is traveled even by
they who study the fire and other vidyās. In the Brahma-tarka it is said:
dvāv eva mārgau prathitāv
arcir-ādir vipaścitām
dhūmādiḥ karmiṇāṁ caiva
sarva-veda-vinirṇayāt
"Two paths are famous. The path beginning with light is traveled by they who
are enlightened with transcendental knowledge, and the path beginning with
smoke is traveled by they who perform Vedic rituals. That is the conclusion of all
the Vedas."
This being so, it is understood that the scriptures describe a single path for the
enlightened souls, and therefore the differences in the descriptions should be
reconciled in the same was they were in the case of the attributes of the Lord. This
is so because the knowledge to be described here is one, even though the scriptural
texts seem to give different explanations. The conclusion, then, is that the path
begins with light. Any other interpretation breaks the real meaning of the Vedic
texts.