Flavius Josephus, Antiquities of the Jews
William Whiston, A.M., Ed.

[29] WHEN Joram had taken upon him the kingdom, he determined to make an expedition against the king of Moab, whose name was Mesha; for, as we told you before, he was departed from his obedience to his brother [Ahaziah], while he paid to his father Ahab two hundred thousand sheep, with their fleeces of wool. When therefore he had gathered his own army together, he sent also to Jehoshaphat, and entreated him, that since he had from the beginning been a friend to his father, he would assist him in the war that he was entering into against the Moabites, who had departed from their obedience, who not only himself promised to assist him, but would also oblige the king of Edom, who was under his authority, to make the same expedition also. When Joram had received these assurances of assistance from Jehoshaphat, he took his army with him, and came to Jerusalem; and when he had been sumptuously entertained by the king of Jerusalem, it was resolved upon by them to take their march against their enemies through the wilderness of Edom. And when they had taken a compass of seven days' journey, they were in distress for want of water for the cattle, and for the army, from the mistake of their roads by the guides that conducted them, insomuch that they were all in an agony, especially Joram; and cried to God, by reason of their sorrow, and [desired to know] what wickedness had been committed by them that induced him to deliver three kings together, without fighting, unto the king of Moab. But Jehoshaphat, who was a righteous man, encouraged him, and bade him send to the camp, and know whether any prophet of God was come along with them, that we might by him learn from God what we should do. And when one of the servants of Joram said that he had seen there Elisha, the son of Shaphat, the disciple of Elijah, the three kings went to him, at the entreaty of Jehoshaphat; and when they were come at the prophet's tent, which tent was pitched out of the camp, they asked him what would become of the army? and Joram was particularly very pressing with him about it. And when he replied to him, that he should not trouble him, but go to his father's and mother's prophets, for they [to be sure] were true prophets, he still desired him to prophesy, and to save them. So he swore by God that he would not answer him, unless it were on account of Jehoshaphat, who was a holy and righteous man; and when, at his desire, they brought him a man that could play on the psaltery, the Divine Spirit came upon him as the music played, and he commanded them to dig many trenches in the valley; for, said he, "though there appear neither cloud, nor wind, nor storm of rain, ye shall see this river full of water, till the army and the cattle be saved for you by drinking of it. Nor will this be all the favor that you shall receive from God, but you shall also overcome your enemies, and take the best and strongest cities of the Moabites, and you shall cut down their fruit trees, ¹ and lay waste their country, and stop up their fountains and rivers."