Joshua arose up early in the morning, and mustered the people, and went up, he and the elders of Israel, before the people to Ai.
The dramatic picture here is that of the total armies of both Bethel and Ai rushing down the steppes to destroy what they have mistakenly supposed to be the defeated Israelites.  What a foolish, headlong rush into disaster!  Men wonder how such a thing could happen, but it has happened often.  Look at the example of Pharaoh rushing into the sea-bed itself where a quarter of a million of his best troops along with the Pharaoh himself went "gurgling down."  We must go a little further and affirm with Pink that the same thing is also going on right this very moment in sinners who have not turned to the Lord: