The cities of Ephraim - This conquest from the kingdom of Israel is referred to, 2 Chronicles 15:8; but when it was made we do not know.

And he placed forces in all the fenced cities of Judah,.... A considerable number of soldiers, to defend them should they be attacked:

and set garrisons in the land of Judah: on the frontiers and borders of it, to protect it:

and in the cities of Ephraim; soldiers to keep garrison there:

which Asa his father had taken; see 2 Chronicles 15:8.

He placed forces (חיל) in all the fenced cities of Judah, and garrisons (נציבים, military posts; cf. 1 Chronicles 11:16) in the land of Judah, and in the cities of Ephraim, which is father Asa had taken; cf. 2 Chronicles 15:8. God blessed these undertakings. Jahve was with him, because he walked in the ways of David his ancestor, the former ways, and sought not the Baals. The former ways of David are his ways in the earlier years of his reign, in contrast to the later years, in which his adultery with Bathsheba (2 Samuel 11) and the sin of numbering the people (1 Chronicles 21) fall. הבּעלים are all false gods, in contrast to Jahve, the one God of Israel; and here the word designates not only the Baal-worship properly so called, but also the worship of Jahve by means of images, by which Jahve is brought down to the level of the Baals; cf. Judges 2:11. The ל before בּעלים stands, according to the later usage, as a sign of the accusative. In the last clause of 2 Chronicles 17:4, "and not after the doings of Israel" (of the ten tribes), הלך, "he walked," is to be repeated. The doing of Israel is the worship of Jahve through the images of the golden calves, which the author of the Chronicle includes in the לבּעלים דּרשׁ.

And he placed forces in all the fenced cities of Judah, and set garrisons in the land of Judah, and in the cities of Ephraim, which Asa his father had taken.

17:1-19 Jehoshaphat promotes religion in Judah, His prosperity. - Jehoshaphat found his people generally very ignorant, and therefore endeavoured to have them well taught. The public teaching of the word of God forms, in all ages, the great method of promoting the power of godliness. Thereby the understanding is informed, the conscience is awakened and directed. We have a particular account of Jehoshaphat's prosperity. But it was not his formidable army that restrained the neighbouring nations from attempting any thing against Israel, but the fear of God which fell upon them, when Jehoshaphat reformed his country, and set up a preaching ministry in it. The ordinances of God are more the strength and safety of a kingdom, than soldiers and weapons of war. The Bible requires use to notice the hand of God in every event, yet this is little regarded. But let all employ the talents they have: be faithful, even in that which is little. Set up the worship of God in your houses. The charge of a family is important. Why should you not instruct them as Jehoshaphat did his subjects, in the book of the law of the Lord. But be consistent. Do not recommend one thing, and practise another. Begin with yourselves. Seek to the Lord God of Israel, then call upon children and servants to follow your example.