Stephen and Alex Kendrick. Nashville: B&H Publishing Group, 2013 (Revised and Updated). 235 pp. (Paperback). First published in 2008, “The Love Dare” has mushroomed into an empire. Five years later, 5 million copies are in print, along with an attendant devotional book, a version for parents, a Bible study and a prominent place in the movie “Fireproof.”  The authors promise…