Albert Barnes Commentary Deuteronomy 3:5

"All these were cities fortified with high walls, gates, and bars; besides the unwalled towns a great many." — Deuteronomy 3:5 (ASV)

Gates, and bars - literally, “Double gates and a bar.” The stone doors of Bashan, their height pointing to a race of great stature, and the numerous cities (deserted) exist to illustrate the statements of these verses.