The fear of the Lord fell on all the kingdoms of the lands surrounding Judah.

2 Chronicles 17:1-19
The Lord was with Jehoshaphat because in his early years he walked in the ways his father David had followed. He sought the God of his father and followed his commands rather than the practices of Israel.
In the third year of his reign he sent his officials to teach in in the towns of Judah. With them were certain Levites and the priests. They taught throughout Judah, taking with them the Book of the Law of the Lord.
The fear of the Lord fell on all the kingdoms of the lands surrounding Judah.
The Chronicler gives Jehoshaphat, a reforming king like Asa, much more space.
Jehoshaphat builds up strong army and defences. He arranges for the people to be taught the law. And he is much respected by the surrounding nations.
The worship of foreign gods clearly continues in the kingdom, since Jehoshaphat destroys their shrines, as his father had done.
Why?
A nation fear the Lord so affect all the kingdoms of the lands surrounding them.
People do not know the Lord so the king sent officials and priests, Levites to teach people fear the Lord and the Law of the Lord.
How?
Fear the Lord throughout whole nation can affect surrounding nations, so a family fear the Lord may affect surrounding neighbors.