וַיֹּ֙אמֶר֙ יְה֣וֹשָׁפָ֔ט יֵ֥שׁ אוֹת֖וֹ דְּבַר־יְהוָ֑ה וַיֵּרְד֣וּ אֵלָ֗יו מֶ֧לֶךְ יִשְׂרָאֵ֛ל וִיהוֹשָׁפָ֖ט וּמֶ֥לֶךְ אֱדֽוֹם׃
And Jehoshaphat said: ‘The word of the LORD is with him.’ So the king of Israel and Jehoshaphat and the king of Edom went down to him.
Read halakhic rulings (Jewish law) on II Kings 3:12: and classical halakhic sources.