They taught throughout Judah, taking with them the Book of the Law of the LORD. They went throughout the towns of Judah and taught the people.
Here we find concerning Jehoshaphat, I. What a wise man he was. As soon as he came to the crown he strengthened himself against Israel, Ch2 17:1. Ahab, an active warlike prince, had now been three years upon the throne of Israel, the vigour of his beginning falling in with the decay of Asa's conclusion.
Commenting on 2 Chronicles 17:1-9
And they taught in Judah,.... The people their duty to God and man: and had the book of the law of the Lord with them; as the rule of their instruction, and the people's obedience; out of this they taught them, and by it confirmed what they taught, and enforced it with the divine authority: and went about throughout all the cities of Judah; not...
the book of the law--that is, either the whole Pentateuch or only the book of Deuteronomy, which contains an abridgment of it.