The Vedanta Sutras of Badarayana, Commentary by Sankara (SBE38), tr. by George Thibaut  at sacred-texts.com
16. And (scripture) declares (Brahman) to consist of that (i.e. intelligence).
And scripture declares that Brahman consists of intelligence, is devoid of any other characteristics, and is altogether without difference; 'As a mass of salt has neither inside nor outside, but is altogether a mass of taste, thus, indeed, has that Self neither inside nor outside, but is altogether
a mass of knowledge' (Bri. Up. IV, 5, 13). That means: That Self has neither inside nor outside any characteristic form but intelligence; simple non-differentiated intelligence constitutes its nature; just as a lump of salt has inside as well as outside one and the same saltish taste, not any other taste.