I think that the quote from the Bhagavad-Gita really fits Holden because he has his way of life that he follows that wouldn't necessarily work for other people.  I think we saw how much Holden really values his way of life when he goes through the patch of depression and almost to suicide when he goes against what he believes and hires a prostitute.  A lot of what Holden believes is rooted in the deaths and traumatic experiences he has had.

I found a quote when I was watching Criminal Minds, they have a famous/not so famous quote at the beginning and end of their episodes.  "A belief is not merely an idea the mind possesses. It is an idea that possesses the mind.".  I feel like this quote very much suits Holden because  he is very much immersed in his perspective view of reality.  There are many views of reality, all of them unique to each person that has them, all of them true.  Yet people still try to get others to see their view, not understanding that just as they have their point of view, so does the other.