Because the palaces shall be forsaken; the multitude of the city shall be left; the forts and towers shall be for dens for ever, a joy of wild asses, a pasture of flocks; The palaces shall be forsaken - The house of the sanctuary (the temple) shall be destroyed. - Targum.
The forts "Ophel" - It was a part of Mount Zion, rising higher than the rest, at the eastern extremity, near to the temple, a little to the south of it; called by Micah, Micah 4:8, "Ophel of the daughter of Zion. "It was naturally strong by its situation; and had a wall of its own, by which it was separated from the rest of Zion.