'Fortified Cities' in the Bible

So the king of the north shall come, and cast up a mount, and take the most fortified cities: and the arms of the south shall not withstand, neither his chosen people, neither shall there be any strength to withstand.

During a time of peace, he will come into the richest parts of the province and do what his fathers and predecessors never did. He will lavish plunder, loot, and wealth on his followers, and he will make plans against fortified cities, but only for a time.