24. The word “light” refers to Brahman on account of the mention of feet in a connected passage.
The Upanishad speaks of that light which shines above heaven and instructs one to meditate upon it. The question arises whether this refers to physical light or to Brahman.
The sutra establishes that it is Brahman, because a preceding passage describes the Purusha as having one foot as all beings and the remaining three feet as immortal in heaven. The later mention of light connected with heaven therefore continues the same Brahman-topic.
25. If it is objected that the passage refers only to the Gayatri metre because it is mentioned earlier, that is not so.
The metre is used as a means for fixing the mind upon Brahman. The instruction is not to meditate upon syllables as such, but upon Brahman as connected with the Gayatri.
This agrees with nearby passages which clearly establish Brahman as the chief topic.
26. The representation of beings, earth, body, and heart as the feet is possible only if Brahman is intended.
These cannot meaningfully be the feet of the Gayatri metre, which is merely a collection of syllables. Therefore Gayatri here signifies Brahman as associated with the metre.
This same Brahman is again recognised as “light” in the later passage.
27. If it is said that the Brahman in the Gayatri passage cannot be the same as the Brahman described as light because of difference in specification, this objection does not stand.
There is no contradiction in saying that Brahman is in heaven in one place and above heaven in another. Both descriptions may refer to the same transcendent reality from different contemplative standpoints.
Therefore the word “light” is to be understood as Brahman.