“The son of King Asa Jehoshaphat succeeded him. He strengthened himself against Israel. He placed forces in all the fortified cities of Judah. He set garrisons in the land of Judah and in the cities of Ephraim which his father King Asa had taken.”
There was not that much about King Jehoshaphat in 1 Kings, as this biblical author expanded on his role. Right from the beginning, he strengthened himself against the northern Israel kingdom. He fortified all the cities of Judah like his father and grandfather. He also sent troops to these cities and those in Ephraim that his father had taken. It sounds like the civil war between the north and south is about to heat up.