Hastings' Dictionary of the Bible (1898)
LOCK. The doors of the ancient Hebrews were secured by bars of wood or iron, though the latter were almost entirely appropriated to the entrance of fortresses, prisons, and towns. Thus we find it mentioned in 1 Kgs 4:13, as something remarkable concerning Bashan that there were threescore great cities having walls and brazen bars. These were almost the only locks known in early times, and they were furnished with a large and clumsy key, which was applied to the bar by pushing the whole arm through an orifice from the outside Cant. Song 5:4.
There were also smaller contrivances for inner doors, Jud 3:24, and probably projecting pieces by which to push the bolt with the hand. See Key.