Hemingway uses the book to explain the brutality of war and the burdens it places on those who become its victims. It's a lesson that Lieutenant Henry learns early in the book, and it's a lesson that we as a society should keep in mind especially in these ever-cautious times in which we live. It also gives the reader a chance to see the insight of those who participated in the wars, and in Chapter XXVI we are reminded of the opinions of these people through statements made by the priest in Henry's quarters. He proclaims: “You can't believe how it happened. Except you've been there and know what it can be like. Many people became aware of the war this summer. Officers who I thought would never realize it, realize it now.