I Kings 22:41 Midrash

וִיהֽוֹשָׁפָט֙ בֶּן־אָסָ֔א מָלַ֖ךְ עַל־יְהוּדָ֑ה בִּשְׁנַ֣ת אַרְבַּ֔ע לְאַחְאָ֖ב מֶ֥לֶךְ יִשְׂרָאֵֽל׃

And Jehoshaphat the son of Asa began to reign over Judah in the fourth year of Ahab king of Israel.

Read midrashic interpretation of I Kings 22:41: and classical rabbinic exegesis.