In the first group of six chapters, the realisation of the real nature of the individual self as forming the ancillary to the worship of Bhagavan Vasudeva, the Supreme Brahman, the supreme object of attainment, has been taught. It is also taught therein that it can be accomplished by two worthy paths, namely, Jñana Yoga and Karma Yoga. Next, in the middle group of six chapters, intense and one-pointed devotion to Bhakti Yoga, preceded by the true knowledge of the Lord, the supreme goal, and His glory, has been propounded. It was also taught in a secondary sense that Bhakti Yoga constitutes the means for those who wish for great sovereignty (Aishvarya) and also for those who aspire after the state of isolation (Kaivalya) of the self. In the next group of six chapters, the topics propounded in the first two group are examined. These are: The attributes of the material body and of the self, the universe as the combination of these, the Ruler, His true nature, the real nature of Karma, Jñana and Bhakti and the ways of practising these. Now in the thirteenth chapter the following topics are discussed: (1) the nature of the body and the self; (2) examination of the real nature of the body; (3) the means for the attainment of the disembodied self; (4) the examination of the real nature of the self in disembodied state; (5) the cause of association of such a self with matter, and (6) the mode of discriminating between the body and the self.

The body which is cognised in identity with the experiencing self by co-ordinate predication(Samanadhikaranya) in the propositions, ‘I am a god, ‘I am a man,’ ‘I am fat,’ ‘I am slender’ etc., is described by those who know the real nature of the body as only the Field (Kshetra) of experience for the experiencing self, who is distinct from the body. Those who know this, namely, those who know the exact nature of the self, call It the Field-knower (Kshetrajña). That knower who knows the body, as divided into its different members and as their collectivity, can say ‘I know it, the body, as an object.’ The person with this perception is the one who is called the Kshetrajña or the Field-knower, who must necessarily be different from the Field (Kshetra), which is the object of this knowledge. It is true that at the time of perceiving an object like a pot which is different from one’s body, the seer who thinks ‘I am a god who sees it’ or ‘I am a man who sees it’ etc., is putting himself as identical with the body through co-ordinate predication. In the same way he experiences the body as an object of knowledge when he says ‘I know this body.’ Thus if the body is an object of knowledge, it must be different from the knowing self. Therefore, the Field-knower (Kshetrajña), the knower, is other than the body which is an object of knowledge like a jar, etc. But this knowledge which arises by way of co-ordinate predication is justified on the ground that the body is inseparable from oneself; for it constitutes an attribute of the self like ‘cow-ness’ of the cow etc. The knowing self is however unique in being an eternal and subtle form of knowledge. But this is inaccessible to the ordinary man’s organs of vision; it is accessible only to a mind refined by Yoga. The ignorant see the knower only in the form of Prakrti because of close proximity to or union with Prakrti. Shri Krishna thus declares later on: ‘When in identification with the Gunas he departs or stays or experiences, the deluded perceive him not. They, who have the eye of knowledge, see’ (15.10).