Mundaka-2-1-1-tadetat satyaṃ

Sri Shankara’s Commentary (Bhashya) translated by S. Sitarama Sastri

Com.—Everything made, as the result of apara vidya has already been stated. That entity known as Purusha from which samsara derives its strength, from which, as its immortal source, it proceeds and into which it is again absorbed is true; the subsequent portion of the book is begun for the purpose of explaining him, who being known, all will become known and who is the subject of ‘Brahinavidya.’ The satyam or truth which is the subject of the apara vidya and which is in the nature of the fruits of karma is only relatively true; but this which is the subject of para vidya is absolutely true, being defined as absolute existence. This satyam is real, being the subject of knowledge; the other mtyam is false, being the subject of ignorance. How could men directly cognize the immortal and real Purusha, seeing that it is altogether beyond the reach of direct perception. To this end, the Sruti gives an example: ‘As from the fire well-fed sparks, i.e., particles of fire issue forth by thousands like fire in their form; so, from the immortal abode described, diverse jivas, diverse because of the difference of conditions, i.e., in their various bodies, come into existence. Just as from akas, the spaces enclosed as it were within the limits of a pot, etc.’ As these spaces undergo varieties corresponding to the varieties of their conditions such as pot, etc., so also the jivas according to the varieties of their bodies created by names and forms. Th e jivas are absorbed into the immortal purusha when the bodies conditioning them cease to exist, as the various cavities cease to exist, when the pot, etc., cease to exist. As the origin and destruction of the various cavities in the akas are due to its being enclosed in a pot, etc., so also the cause and the absorption of the jiva are due to the akshara, being conditioned by bodies bearing names and forms.

Links
Various resources on the Mundakopanishad
Upanishad Series – Mundakopanishad Commentary by Swami Chinmayananda