God has said literally in the above scripture "I change not"
Yes, he did not change his opinion on that specific occasion. Otherwise he changed his opinion many times - often after haggling with humans.
Read the bible! You can easily see your God's flexibility in his dialogs with Abraham or Moses. Don't just pick some quote from the bible that supports your idea and ignore all the rest that contradicts it.
Sure, just like it must have taken courage for Judas to betray Jesus or for Benedict Arnold to become a traitor to the American Revolution.
Then Jesus is for you a traitor too? He said "Turn the other cheek", knowing that his God JHWH said 1000 years before "Thou shalt give life for life, eye for eye, tooth for tooth, hand for hand, foot for foot, burning for burning, wound for wound."
The bible is full of examples how your God changed over time and adapted to the changing ethics of human society. Just read it with a open mind and learn from it. If the bible would have been continued in the last 2000 years, you'd probably read how your God some day accepted the Copernican system, Newtonian mechanics, Relativity Theory, the Big Bang, and eventually even the UN charter of human rights.
