Don't say that no one other than Arjun was eligible to understand that divine knowledge or had enough devotion. God should not discriminate based on the basis of eligibility and devotion if everyone is equal according to him. Not a single character we know from history is/was really a God it seems.All religious characters are man made Gods/Messangers of God. Noone can understand the true character of mother Nature (which itself has consciousness but its brutal), what it wants, why does it exist.
No questions on Teachings of Bhagvad Geeta as little as I have read. It teaches a lot.