The Vedanta Sutras of Badarayana, Commentary by Sankara (SBE38), tr. by George Thibaut  at sacred-texts.com
39. Better than this is the other (state of belonging to an âsrama), on account of the indicatory marks.
'Than this,' i.e. 'than standing between,' a better means of knowledge it is to stand within one of the âsramas, since this is confirmed by Sruti and Smriti. For scripture supplies an indicatory mark in the passage, 'On that path goes whoever knows Brahman and who has done holy
works (as prescribed for the âsramas) and obtained splendour' (Bri. Up. IV, 4, 9); and Smriti in the passage, 'Let a Brâhmana stay not one day even outside the âsrama; having stayed outside for a year he goes to utter ruin.'