The Vedanta Sutras of Badarayana, Commentary by Sankara (SBE38), tr. by George Thibaut  at sacred-texts.com
8. And on account of (the Brahman to which the Souls are led) being qualified (in another passage).
That the soul's going has for its object the effected Brahman, we conclude from another scriptural passage also which qualifies Brahman in a certain way, 'He leads them to the worlds of Brahman; in these worlds of Brahman they live for ever and ever' (Bri. Up. VI, 2, 15). For it would be impossible to qualify the highest Brahman by means of the plural number ('worlds'); while the plural number may be applied to the lower Brahman which may abide in different conditions.--The term 'world' also can directly denote only some place of enjoyment falling within the sphere of effects and possessing the quality of being entered into, while it must be understood in a metaphorical sense in passages 1 such as 'Brahman is that world '(Bri. Up. IV, 4, 23).--And also what the text says concerning an abode and some one abiding within it ('in these worlds of Brahman,' &c.), cannot be directly understood of the highest Brahman.--For all these reasons the leading of the souls has the lower Brahman for its goal.
But even on this interpretation the word 'Brahman' is inappropriate, as it has been proved that Brahman is the
cause of the origination and so on of the entire world.--To this objection the next Sûtra replies.
390:1 Where the term 'world' is applied to the highest Brahman.