The Question and Answer section for Bhagavad-Gita is a great resource to ask questions, find answers, and discuss the novel.
That would be the "soul".
Where in the text are you referring to?
One of the more subtle themes in the Gita is the contrast between faith and evidence -- and humanity's inclination to want to "see" something in order to believe it. Indeed, one of the central tenants of Buddhism is that we must believe what we...