Preamble

The  two prakritis of the Lord, the higher and the lower, were discussed in the  Seventh Chapter. It has been said that all created beings are born of them.  (7.6). This topic dealing with Prakrti,  matter and Purusha, spirit are elaborated in this section. Matter functions  with several modifications and qualities while spirit functioning through them  all is but one and the same. The union of spirit with matter produces a living  being. The supreme Self, being the same, expresses differently in different  individuals.

The path to Self-realization begins with action,  passing through knowledge, it ends in meditation. Those who cannot pursue the  path all by themselves can still reach the Self by surrendering to and  following a spiritual master. 

Spiritual growth is marked by recognizing the  homogeneous principle in the heterogeneous variety of beings. Perceiving the  Imperishable in the perishable world, the seeker realizes Brahman as the  substratum in the diversified existence of all beings. He becomes one with  Brahman.

The  supreme Self within does not act; nor is It tainted by the actions of beings.  It remains ever immaculate like space which is never polluted by the different  objects occupying it. He who recognizes the supreme Self in the manifold beings  is endowed with jnanachakshu, the Eye of Wisdom, with which he perceives  the Supreme.

The Text

NATURE  AND SPIRIT

prakritim purusham chaiva viddhyanaadee ubhaavapi
    vikaaraamshcha gunaamshchaiva viddhi prakritisambhavaan // 13.20 //

Know you that Prakriti and Purusha  are both without beginning and know you also that all forms and gunas are born  of Prakriti.

In Chapter 7 Sri Krishna said  that His Prakriti falls under two categories viz. the Higher and the Lower. In  this Chapter both these are explained as the Knower of the Field (Kshetrajna,  Purusha) and the Field (Kshetra, prakriti). It was also stated earlier that  both the Higher and Lower Matter together constitute the source of creation.  The same thought is repeated here as the Field and the Knower of the Field  together form the origin of all beings.

Prakriti, Matter or nature is  inert.  Matter is that out of which all  forms (from intelligence down to the gross body) and gunas (qualities such as  sattva, rajas and tamas, which manifest themselves in the form of pleasure,  pain delusion so on,) come into existence. All changes or modifications are  related to Matter. Prakriti is maya, the sakti or power of the Lord. It is the  cause of the manifestation of the relative universe.

Since Prakriti or maya is the  eternal source of all forms and gunas, Brahman (Purusha) remains ever  changeless and immutable. Purusha, Self, Soul, Spirit, is the changeless  substratum in the presence of which all changes take place.

Matter (Prakriti) and Spirit  (Purusha) are both beginningless. They are the two aspects of Iswara, the Lord.  As the Lord is eternal so also is His two aspects Matter and Spirit. The play  of Matter and Spirit causes the origin, preservation and dissolution of the  Universe.

FUNCTIONS  OF PRAKRITI AND PURUSHA

kaaryakaaranakartrutwe hetuh prakritiruchyate
    purushah sukhaduhkhaanaam bhoktritwe heturuchyate // 13.21 //

Prakriti is said to be the cause  of the generation of the body and the organs and Purusha is said to be the cause  of the experience of pleasure and pain.

Prakriti (nature) is the material  from which the body and the sense organs are produced. The five elements out of  which the body is made and the five sense-objects are included under the term  ‘body’ or ‘karya’ used in the Verse. The sense organs are thirteen  namely five organs of perception, five organs of action, the mind, intellect  (buddhi), and I-consciousness (ahamkara). Pleasure, pain, delusion and the rest,  which are born of three gunas of prakriti, are included under the term organs  or ‘karana’ since they cannot exist independently of the sense-organs.

Purusha and Prakriti are stated  to be the cause of samsara or phenomenal existence. Prakriti transforms itself  into body and senses, as also into pleasure, pain and so on and Purusha  experiences pleasure and pain. This union between Purusha and Prakriti makes  relative life possible. Even though the Purusha, the Soul, identifies Himself  with the body and appears to experience pleasure and pain, yet in reality He  remains unchanging. It is this apparent experience which constitutes His  illusory world or samsara and which makes Him a samsari or phenomenal being.

It should be clearly understood that  although the term Purusha used here is synonymous with jiva, the individualized  soul, or Kshetrajna, the Knower of the Field, or bhokta, the enjoyer, it  should not be confused with the Paramatman or Brahman or the Highest Self. The  term Purusha is used here merely as an intelligent principle and a conditioned  being. Again, this should not be construed that there are two separate  purushas; the same one purusha is seen from two different angles. In the Gita,  no distinction is made between the knower of the Field and the Supreme Lord,  Paramatman, Brahman.

This should be kept in view when  we study Chapter 15.