Continuing the series of posts I have done showing what a consistent role religion has played in the history of the USA, here is a description and photo from the Smithsonian Institute:
Religion has an essential role in military history, which is reflected in military material. Steel-covered New Testaments were popular keepsake gifts for soldiers going off to fight in World War II. Advertised in newspapers and magazines as protection from bullets, the small books were designed to be carried in the pocket over one's heart as both symbol and shield.
Read more on the Smithsonian's National Museum of American History