The Devil is Very Real!

For we do not wrestle against flesh and blood, but against ​the rulers, against the authorities, against the cosmic powers over ​this present darkness, against the spiritual forces of evil in the heavenly places (Ephesians 6:12).

One of the things that surprised me when I first read the New Testament seriously was that it talked so much about a Dark Power in the universe - a mighty evil spirit who was held to be the power behind death and disease and sin. The difference is that Christianity thinks this Dark Power was created by God, and was good when he was created, and went wrong. It is a war between independent powers. It thinks it is a civil war, a rebellion and we are living in part of the universe occupied by the rebel. Enemy occupied territory - that is what the world is. Christianity is the story of how the rightful King has landed, you might say in disguise, and is calling us all to take part in His great campaign of sabotage.
                                         
                                                          --C. S. LEWIS, Mere Christianity