John Gill's Bible Commentary Ver. 5. All these cities were fenced with high walls, gates, and bars , etc.] That is, all the cities in the kingdom of Bashan; and though they were, it hindered not their falling into the hands of the Israelites; and this might serve to encourage them against those fears they were possessed of by the spies, with respect to the cities in the land of Canaan; (see Numbers 13:28 Deuteronomy 1:28) besides unwalled towns a great many ; small towns and villages adjacent to the several cities, as is common.
Matthew Henry Commentary
Verses 1-11 - Og was very powerful, but he did not take warning by the ruin of Sihon and desire conditions of peace. He trusted his own strength, and so wa hardened to his destruction. Those not awakened by the judgments of God on others, ripen for the like judgments on themselves.
Original Hebrew כל3605 אלה428 ערים5892 בצרת1219 חומה2346 גבהה1364 דלתים1817 ובריח1280 לבד905 מערי5892 הפרזי6521 הרבה7235 מאד׃3966