The Vedanta Sutras of Badarayana, Commentary by Sankara (SBE38), tr. by George Thibaut  at sacred-texts.com
REVERENCE TO THE HIGHEST SELF!
1. (On the soul's) having entered (into the highest light), there is manifestation (of its own nature); (as we infer) from the word 'own.'
'Thus does that serene being, having risen out of this body and entered into the highest light, manifest itself by its own nature' (Kh. Up. VII, 12, 3). Regarding this text a doubt arises whether the Self 1 manifests itself through some adventitious distinction--as the Self (of him who possesses the lower knowledge only) does in the world of the gods and other abodes of enjoyment--or only through its own Self.--The pûrvapakshin maintains that, as in other places, here also the manifestation takes place through some adventitious characteristic; because release also is a fruit (like other fruits, e.g. svarga), and because 'manifestation' means as much as origination. If the manifestation took place only through the Self's own nature, it would already appear in the Self's former states: for a thing's own nature is never absent from it. The Self therefore manifests itself by means of some adventitious distinction.
To this we make the following reply. It manifests itself through its Self only, not through any other attribute.--Why so?--On account of the word 'own' in the clause 'by its own nature.' For on the other view the qualification conveyed by 'own' would be unmeaning.--But may not the term 'own' merely indicate that that form belongs to that which manifests itself?--Not so, we reply. This is a point which would not require to be stated. For as in
whatever form a thing manifests itself that form necessarily belongs to it, the qualification 'own' would be devoid of purport. It has a meaning, on the other hand, if it denotes the Self, the sense conveyed then being that the manifestation takes place only through the nature of the Self, not through any other, adventitious, nature.--But, as a thing cannot be without its own nature, what difference is there between the Self's former states and its present state (after the manifestation)?--To this question the next Sûtra replies.
405:1 Samprati katurthe pâde paravidyâphalaikadeso brahmabhâvâvirbhâvâh, sagunavidyâphalam ka sarvesvaratulyabhogatvam avadhârayishyate, tatrâparavidyâprâpyam uktvâ paravidyâprâpyam âha sampadyeti. Ân. Gi.