Vedanta Sutra 4.4.2
2. Manifestation in its own form mentioned in
the Chandogya Upanishad [8.12.3] is the condition of
the Mukta, because that is what Prajapati has promised
to teach in the opening part of the Upanishad. - 539
It is verily the Mukta who manifests itself in its own form. Why? Because of the promise. In the opening sentence [8.7.1] Brahma describes the condition of the Mukta Jiva thus:-
"The Self which is free from sin, free from old age, free from death and grief, from hunger and thirst, which desires nothing but what it ought to desire, and imagines nothing but what it ought to imagine, that it is which we must search out, that it is which we must try to understand. He who has searched out that Self and understands it, obtains all worlds and desires. [Thus spake Prajapati.]"
This shows the condition of the Mukta Jiva, and Prajapati promises to teach Indra this Mukta condition, by saying "I shall explain the true Self further to you." This promise is given several times. It is first given when Indra, dissatisfied with the waking Self, comes back to Prajapati, again to be taught, and Prajapati says [8.9.3] "I shall explain it further to you. Live with me another thirty-two years". Then he explains to him the Self in dream, and when Indra is not satisfied with that, he teaches him the Self in dreamless sleep; and when Indra is not satisfied with that even, Prajapati at last describes to him the true Self, free from all the three conditions of waking, etc., and teaches the condition of the Self in the state of Mukti in these terms:
"Maghavat, this body is mortal and always held by death. It is the abode of that Self which is immortal and without body. When in the body (by thinking this body is I amd I am this body) the Self is heald by pleasure and pain. But when he is free of the body (when he knows himself different from the body), then neither pleasure nor pain touches him.
"The wind is without body, the cloud, lightning, and thunder are without body, (without hands, feet, etc). Now as these arising from this heavenly ether (space), appear in their own form, as soon as they have approached the highest light.
"Thus does that serene being, arising from this body, appear in its own form, as soon as it approaches the Highest Light. He (in that state) is the highest person (uttama pUruSa). He moves about there laughing (or eating), playing, and rejoicing (in his mind), be it with women, carriages, or relatives, never minding the body into which he was born."
This final teaching of Prajapati is in accordance with his final promise given in [Chandogya Upanishad] 8.11.3, where he says "I shall explain the true Self further to you and nothing more than this." Thus, because of this promise, the teaching about the "Self appearing in its own form" must relate to the condition of the Muktas. Therefore, Mukti is indeed the manifestation of one's own form, which consists in remaining in one's own natural condition, free from the body, etc., which are produced through the effect of Karmas. This bodiless condition, free from pleasure and pain, is Mukti.
This condition is described in the text as coming subsequent to the approaching of the soul to the Highest Light. After the Highest Light is reached, there appears this manifestation.
Doubt: But on this point a further doubt is raised. What is this Highest Light? Is it the solar orb, for light generally means the sun, or is it the Supreme Brahman?
Purvapaksa: The opponent maintains the view that the Highest Light refers here to the solar orb. Because in the Mundaka Upanishad it is said that it is after reaching the sun that one gets Mukti. The present passage also says that it is after reaching the Highest Light that one manifests his own nature. Therefore, the Highest Light of the Chandogya passage is the solar orb mentioned in the Mundaka Upanishad 2.2.11 and it is the same solar orb which comes as the Adityaloka in the ārchirādi path already mentioned before.
Siddhānta: This view is set aside in the next sūtra.
Chandogya Upanishad 8.7.1:
ya ātmā apahata-pāpmā vijaro vimṛtyur viśoko vijighatso'pipāsaḥ satya-kāmaḥ satya-saṁkalpaḥ, so'nveṣṭavyaḥ, sovijijñāsitavyaḥ sa sarvāṁś ca lokān āpnoti sarvāṁś ca kāmān, yas tam ātmānam anuvidya vijānāti: [iti ha prajā-patir uvāca].
Chandogya Upanishad 8.9.3:
evam evaiṣa, maghavan, iti hovāca, etam tv eva, te bhūyo 'nuvyākhyāsyāmi; vasāparāṇi dvātriṁśataṁ varṣāṇīti.
evam evaiṣa, maghavan, iti hovāca, etam tv eva te bhūyo 'nuvyakhyāsyāmi, no evānyatraitasmāt.
Mundaka Upanishad 2.2.11:
na tatra sūryo bhāti, na candra-tārakam, nemā vidyuto bhānti, kuto'yam agniḥ.
tam eva bhāntam anubhāti sarvam, tasya bhāsā sarvam, idaṁ vibhāti.