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

"I shall now ask about the Supreme Personality of Godhead, who is described
in the Upaniṣads."
We may note in this connection that the word aupaniṣada means "that glorious
person who is described in the Upaniṣads."
We may also note that the word īkṣateḥ is bhāva (passive), and it is formed by
adding the affix tip-pratyaya. The unusual usage here is ārṣa (a certain degree of
grammatical liberty allowed to an exalted author).
That the Supreme Personality of Godhead may be described in words is also
confirmed by the following statement of Kaṭha Upaniṣad (2.15):
sarve vedā yat-padam āmananti
"All the Vedas describe the feet of the Supreme Personality of Godhead."
When it is said that Brahman cannot be described in words, the intention is
that He cannot be completely described in words. In the same way it is sometimes
said that no one can see Mount Meru because no one can see the entire mountain,
but only small parts of it at any one time. Without accepting this understanding,
that Brahman is not completely expressible by words or understandable by the
mind, we would not properly understand the meaning of the scritpural statements
yato vāco nivartate (words cannot describe Brahman), aprāpya manasā saha (the
mind cannot understand Brahman), and yad vacanābhyuditam (No one has the
power to describe Brahman with words). These statements explain that Brahman
cannot be completely described in words.
That Brahman can to some extent be described with words does not contradict
the fact that Brahman reveals Himself by His own wish. The Vedas are actually the
incarnation of Brahman, and therefore Brahman may reveal Himself in the words
of the Vedas.
2. Saṁśaya (doubt): This may be so, but still the Suprme Person described in
the words of the Vedas may be saguṇa (a manifestation of the Lord according to
the modes of material nature), and not the perfect, complete and pure original
Brahman who remains indescribable by words.
If this doubt were to arise, Śrīla Vyāsadeva would answer it in the following
sūtra.
Sūtra 6
gauṇaś cen nātma-śabdāt
gauṇaḥ—Saguṇa Brahman, or the Lord's potencies; cet—if; na—not; ātma—ātma;
śabdāt—because of the word.