Joshua 8:17

Or Beth-el. This city was only a few miles from Ai. The two cities may have had a signal system between them, so that when one was attacked, immediately the other could be alerted and come to the rescue. It may have been the work of the 5,000 in ambush to attack the assisting force from Bethel. The city of Bethel itself was not completely overthrown until later (see Judges 1:22). It is probable that events on the day that Ai was taken inflicted a measure of defeat upon the men of Bethel permitting the postponement of the capture of the city for a time.