pañca-kośa-viveka

yastu vijñānavān bhavati samanaskaḥ sadā śuciḥ |

sa tu tat padamāpnoti yasmād bhūyo na jāyate ||1.3.8||

Suppose there is one who is with a discriminative intellect, with a (disciplined)

mind, and ever pure. He definitely attains that goal from which he is not reborn.

Whereas, if one has discriminative knowledge between ātma and anātmā, discipline, and an ever pure mind as a charioteer, he will attain the ultimate goal, and will not be born again in the world of bondage.

What is that goal which was talked about in the 7th and 8th mantra?

vijñānasārathiryastu manaḥ pragrahavān naraḥ |

so’dhvanaḥ pāramāpnoti tad viṣṇoḥ paramam padam ||1.3.9||

That person who has a discriminative intellect as the charioteer and who has a

disciplined mind as the reins reaches the destination of the journey. It is the

supreme nature of brahman.

naraḥ - the person (human being), vijñānasārathiryaḥ - who has a discriminative intellect as a driver, and manaḥ pragrahavān - disciplined mind as reins, so’dhvanaḥ pāramāpnoti - attains the final destination of the journey of samsāra. The destination here is in the form of releasing from all bondages. tad viṣṇoḥ paramam padam - that destination is the highest abode of viṣṇuḥ. The word viṣṇuḥ means that which is all-pervading, which is attribute-less paramātmā, the very nature of every individual. Thus, this mantra implies that the destination of the journey is the very nature of the traveller himself. There is no real travel involved; the entire journey is a cognitive journey.

With this mantra, the topic of the means for śreyas is complete.

In the previous verse, we saw that there is no physical reaching of viṣṇuḥ. The only requirement is dropping one’s identification. It is a cognitive journey; thus, śruti gives a progressive elaboration. The method used here is called pañca-kośa-viveka;

discriminating/discernment through five sheaths which we identify with. At each level we commit mistakes, so we have five types of mistakes corresponding to five levels of experience. These sheaths cover the true self, and by analyzing and discarding the wrong identification with each sheath, one can discover the innermost self that pervading each sheath.

In pañca-kośa-viveka, jīvātmā - individual discerning each level:

1.Annamaya-kośa (food sheath - modification of food).

The gross physical body made of food and sustained by food, and resolved in the earth that is in the form of food. It is anātmā because it is perishable, changeable, and objectifiable.

2.Pranamaya-kośa (vital energy sheath).

The life-force (prana) that enables physiological functions (respiration, circulation, digestion, etc). Though subtler than the body, it also changes anytime; therefore it is also not the ātmā.

3.Manomaya-kośa (mental sheath).

The mind (emotions, thoughts, perceptions). Subject to change, pleasure, and pain.Since it comes and goes, it's not the eternal ātmā.

4.Vijnanamaya-kośa (intellect sheath).

The intellect or discriminative faculty. While subtler, it too is a changing instrument  (sometimes sharp, sometimes dull). Hence, still not the ātmā.

5.Ānandamaya-kośa (happiness sheath).

The causal body, experienced in deep sleep and moments of joy. It is the most subtle layer and felt closest to the self, but still conditioned and temporary. Thus it is not ātmā.