The Vedanta Sutras of Badarayana, Commentary by Sankara (SBE38), tr. by George Thibaut  at sacred-texts.com
30. And on account of the denial.
The conclusion arrived at above is confirmed by the fact of scripture expressly denying that there exists any intelligent being apart from the highest Self. Cp. 'There is no other seer but he' (Bri. Up. III, 7, 23). And the same
conclusion follows from those passages which deny the existence of a world apart from Brahman and thus leave Brahman alone remaining, viz. 'Now then the teaching, Not so, not so!' (Bri. Up. II, 3, 6); 'That Brahman is without cause and without effect, without anything inside or outside' (Bri. Up. II, 5, 19).