1 Kings 9:17

And Solomon built Gezer, and Beth-horon the nether,

Solomon rebuilt Gezer and lower Beth-horon. Gezer stood near Joppa on the road between Egypt and Syria. Beth-horon commanded the passes leading from Judea toward Gezer and the coast.

These were strategic cities, and Solomon fortified them to strengthen his own position and to gain benefit from commerce. Placed as they were in the thoroughfares of travel, they could have served to make the true God known to people from many nations passing through. Instead they were used for military and commercial advantage.