The Vedanta Sutras of Badarayana, Commentary by Sankara (SBE38), tr. by George Thibaut [1896] at sacred-texts.com
20. Thus in other cases also, on account of the connexion (of particulars with one and the same vidyâ).
We read in the Brihad-âranyaka (V, 5), 'The true is Brahman,' and, further on, 'Now what is the true, that is the Âditya, the person that dwells in yonder orb, and the person in the right eye.' Having thus declared the different abodes of that true Brahman with reference to the gods and with reference to the body, and having, in what follows, identified its body with the sacred syllables (bhûh, &c.), the text teaches its two secret names (upanishad), 'Its secret name is ahar' with reference to the gods; and 'its secret name is aham' with reference to the body.--A doubt here arises whether these two secret names are both to be applied to the deva-abode of Brahman as well as to its bodily abode, or only one name to each.
The above Sûtra maintains the pûrvapaksha view. Just as certain particulars though recorded elsewhere are yet
to be combined with the Sândilya-vidyâ, so we have to proceed in other cases also, as e.g. the one under discussion, because the particulars mentioned are all connected with one vidyâ. The vidyâ of the True with its double reference to the Devas and to the body is one only, as we infer from the fact of its having one exordium only ('The true is Brahman'), and from the way in which the text interconnects Âditya and the person in the eye. Why then should an attribute belonging to one of the latter not belong to the other also? For, to quote an analogous case, certain rules of life which are prescribed for a teacher--as e.g. having a following of pupils--remain equally valid whether the teacher be in a village or in a wood. For these reasons both secret names equally belong to the Âditya as well as to the person within the eye. This view the next Sûtra refutes.