Joshua 7:3

‘ And they returned to Joshua, and said to him, “Do not let all the people go up, but let about two or three eleph men go up and smite Ai, and do not make all the people toil up to it, for they are but few.” '

The scouts did not see Ai as a large obstacle. They recommended only sending three units up to deal with it in view of its very small population. It was a long hard climb of over a thousand metres in height (three thousand feet) and over twenty four kilometres (fifteen miles) in distance.