In an earlier post I wrote about Spiritual Warfare. Historically we have seen struggles which were clearly seen to be good versus evil. I believe there was a spiritual component to them.
(1) Wars, WWII
While nobody likes war, sometimes it becomes necessary for a nation to defend itself from aggressors. Typically the aggressors are considered evil because they are attacking innocent people, trying to grab more territory, destroying cities and villages, and are generally up to no good. Probably the best examples of evil aggressors were the Nazis and Japanese in World War II. They made their leaders into gods, rather than worship the true God. So I believe WWII was definitely a battle between the forces of good and the forces of evil.
(2) Idol worship
Another struggle is against the “gods” of this world, such as materialism, accumulation of wealth, career, success, etc. There’s nothing wrong with any of these until we make them into idols. When these things dominate our lives and are more important than God, then they become idols. That’s the constant spiritual struggle we face.