The Bhagavad Gita: dharma and atman

I dont know in too much detail but I think the battle was unjust from the opposing side and Arjuna was meant to be on the "good side " fighting evil.

There is another interpretation that the battle of Kurukshetra was never literal, and that the whole Gita is a symbolic representation of the metaphorical battle taking place constantly in the minds of every human being striving towards enlightenment.