Most western armies issued their soldiers small pocket Bibles or prayer books or both upon enlistment. Sometimes in the USA the local church would do the same.
Whatever else one might say about this practice it certainly reflects a time in history when the west was more “christianized” than it is now.
These days someone might be offended and the practice of issuing a prayer book would be mocked.
Thanks to my friend Rob for this translation of a German soldier’s prayer that dates back to the Napoleonic Wars.