'Bars' in the Bible

Also he built Beth-horon the upper, and Beth-horon the nether, fortified cities, with walls, gates, and bars;

For he said unto Judah, Let us build these cities, and make about them walls, and towers, gates, and bars; the land is yet before us, because we have sought Jehovah our God; we have sought him, and he hath given us rest on every side. So they built and prospered.