2 Chronicles 17:1

And Jehoshaphat his son reigned in his stead, and strengthened himself against Israel.

Strengthened himself against Israel. The temper and proceedings of the kings of Israel rendered it necessary for him to prepare vigorous measures of defense on the northern frontier of his kingdom, and these consisted in filling all the fortresses with their full complement of troops, and establishing military stations in various parts of the country, as well as in the cities of mount Ephraim, which belonged to Jehoshaphat (2 Chronicles 15:8).