וַיַּשְׁלֵ֥ם יְהוֹשָׁפָ֖ט עִם־מֶ֥לֶךְ יִשְׂרָאֵֽל׃
And Jehoshaphat made peace with the king of Israel.
Rashi on I Kings
Yehoshofot made peace with the king of Yisroel. Since there was war between Asa his father and Basha the king of Yisroel, it was necessary to say this.