In the last sloka  in Chapter 14, the Lord said that to attain any of the Three - wealth, Kaivalyam or Vaikuntam - He was the only means. So it becomes necessary to explain Who the Lord was. This is explained in Chapter 15 and it is called Purushottama Vidya. The Lord is different from and superior to Chit and Achit. Chapter 15 can be taken as explanation of sloka 27 of Chapter 14. Another interpretation is that in Chapter 13, the Lord explained about body or Achit. In Chapter 14, He explained about atman or Chit. Therefore in Chapter 15, the Lord explains about Paramatman or Iswara, Who is the Lord of both Chit and Achit. Another way to look at, is that from Chapter 2 to Chapter 6, the Lord explained Karma yoga and Gyana yoga and indicated that they were the means to attain atman. From Chapter 7, the Lord explains Bhakti yoga to reach the Lord. In Chapter 15, Who the Lord was, is explained. We will today [7th April 2009] see the summary of Chapter as brought out by Swami Alavandar in his Gitarta Sangraha:
acinmi´sr¯at vi´suddh¯acca cetan¯at purus.ottamah. |
vy¯apan¯at bharan.¯at sv¯amy¯at anyah.pa˜ncada´soditah. 19
The Lord, Bhagavan, is Most Supreme and different from all. Purusha, purusha uttara and Purushottama are the gradings. Many are not even purusha or they are Achit. Among purusha [atman or Chit], there are varieties. But the Lord is the Most Supereme of all. Achin = body, misra = combined, people like us are in this Universe with these bodies combined. We are all Baddhatman. Visuddha = liberated, cetanat = atman. That is Muktatman. They are no longer in contact with the body. Purushottama = the Lord is Superior [to bhaddatman and muktatman]. Why? Because, vyapanat = pervade everywhere, without exception, bharanat = support all and everything, svamyat = possessor and controller of everything. The Lord is the Most supreme because He pervades all, supports all and owns all. This is told in Chapter 15.