Joshua burned Ai and made it a permanently uninhabited mound (it remains that way to this very day).

But Israel did not burn any of the cities located on mounds, except for Hazor; it was the only one Joshua burned.

The Lord says, “I will restore the ruined houses of the descendants of Jacob. I will show compassion on their ruined homes. Every city will be rebuilt on its former ruins. Every fortified dwelling will occupy its traditional site.

You must gather all of its plunder into the middle of the plaza and burn the city and all its plunder as a whole burnt offering to the Lord your God. It will be an abandoned ruin forever – it must never be rebuilt again.

Because you did that, I, the Lord, affirm that a time is coming when I will make Rabbah, the capital city of Ammon, hear the sound of the battle cry. It will become a mound covered with ruins. Its villages will be burned to the ground. Then Israel will take back its land from those who took their land from them. I, the Lord, affirm it!