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

hṛdi hy eṣa ātmā
"The soul resides in the heart."
In the final conclusion the spirit soul, although atomic in size, is, in one sense,
all-pervading throughout the entire material body. This is explained in the
following sūtra.
Sūtra 24
guṇād vālokavat
guṇāt—by quality; vā—or; āloka—light; vat—like.
By quality or like light.
Purport by Śrīla Baladeva Vidyābhūṣaṇa
Although the soul is atomic in size, it pervades the body by the quality of
consciousness. Like light it pervades the entire body. As the sun, although situated
in one place, fills the universe with light, so the soul fills the body with
consciousness. The Supreme Personality of Godhead Himself declares this in
Bhagavad-gītā (13.34):
yathā prakāśayaty ekaḥ
kṛtsnaṁ lokam imaṁ raviḥ
kṣetraṁ kṣetrī tathā kṛtsnaṁ
prakāśayati bhārata
"O son of Bharata, as the sun alone illuminates all this universe, so does the
living entity, one within the body, illuminate the entire body by consciousness."*
When the sun emanates sunlight it does not lose any atoms from its mass, nor
does it become diminished in any way. Rubies and other jewels also emanate light
without losing atoms from their mass or becoming diminished in any way. It is not
possible to say that when light is emanated from them these things become
diminished in size. The light they emanate is their quality, not their mass.
The quality can function in a plane apart from the substance that possesses it.
The author of the sūtras explains this in the following example.