2 Chronicles 20:1-3

Later the Moabites, Ammonites, and some Meunites came to start a war with Jehoshaphat. Messengers came and told Jehoshaphat, “A large army is coming against you from Edom, from the other side of the Dead Sea. They are already in Hazazon Tamar!” (Hazazon Tamar is also called En Gedi.) Jehoshaphat was afraid, so he decided to ask the LORD what to do. He announced that everyone in Judah should fast during this special time of prayer to God.