וְכָל־הַ֨נְּבִאִ֔ים נִבְּאִ֥ים כֵּ֖ן לֵאמֹ֑ר עֲלֵ֞ה רָמֹ֤ת גִּלְעָד֙ וְהַצְלַ֔ח וְנָתַ֥ן יְהוָ֖ה בְּיַ֥ד הַמֶּֽלֶךְ׃
And all the prophets prophesied so, saying: ‘Go up to Ramoth-gilead, and prosper; for the LORD will deliver it into the hand of the king.’
Read midrashic interpretation of II Chronicles 18:11: and classical rabbinic exegesis.