C. S. Lewis is one of my favorite authors of all time. He may have been the first author I started reading outside of the Bible when I became a Christian – now many years ago. Here is a good one from him and more relevant that we probably imagine in a normal day.
Enemy-occupied territory—that is what this world is. Christianity is the story of how the rightful king has landed, you might say landed in disguise, and is calling us all to take part in a great campaign of sabotage.
– C. S. Lewis in Mere Christianity