The Vedanta Sutras, commentary by Sankaracharya (SBE34), tr. by George Thibaut  at sacred-texts.com
20. And the reference (to the individual soul) has a different meaning.
The alleged reference to the individual soul which has been pointed out (by the pûrvapakshin) in the passage complementary to the passage about the small ether ('Now that serene being,' &c., VIII, 3, 4) teaches, if the small ether is interpreted to mean the highest Lord, neither the worship of the individual soul nor any qualification of the subject under discussion (viz. the small ether), and is therefore devoid of meaning.--On that account the Sûtra declares that the reference has another meaning, i.e. that the reference to the individual soul is not meant to determine the nature of the individual soul, but rather the nature of the highest Lord. In the following manner. The individual soul which, in the passage referred to, is called the serene being, acts in the waking state as the ruler of the aggregate comprising the body and the sense-organs; permeates in sleep the nadîs of the body, and enjoys the dream visions resulting from the impressions of the waking state; and, finally, desirous of reaching an inner refuge, rises in the state of deep sleep beyond its imagined connexion with the gross and the subtle body, reaches the highest light, i.e. the highest Brahman previously called ether, and thus divesting itself of the state of specific cognition appears in its own (true) nature. The highest light which the soul is to reach and through which it is manifested in its true nature is the Self, free from sin and so on, which is there represented as the object of worship.--In this sense the reference to the individual soul can be admitted by those also who maintain that in reality the highest Lord is meant.