I don't know much about spiritual warfare. Its a strange concept though, you think of a battle as something two sides fighting to win. Obviously God doesn't need to fight. He gave us tools to fight though and wants us utilizing his power to fight. So winning is the goal, but God doesn't want to make it too easy for us. Why? That I'm not sure, seems like if Jesus said it would be worth plucking out an eye to avoid temptation that God would have a lot of incentives to make temptation less tempting.