The purpose of Bhagavad-gita is to deliver mankind from the nescience of material existence.Every man is in difficulty in so many ways, and in the same way Arjuna also was in difficulty in having to fight in the battle of Kurukshetra.
Arjuna surrendered unto Shri Krishna, and consequently this Bhagavad-gita was spoken. Not only Arjuna, but every one of us is full of anxieties because of this material existence. Our very existence is in the atmosphere of nonexistence. Actually we are not meant to be threatened by nonexistence. Our existence is eternal. But somehow or other we are put into asat. Asat refers to that which does not exist.