Joshua 7 Defeat at Ai

Surprise Attacks Are Full Of Surprises

Achan, the son of Carmi and a soldier in the Israelite army, decides that he doesn't want to participate in the herem and keeps trinkets for himself. Tsk tsk.
God saw, of course, on account of being omniscient. Not surprisingly, he wasn't pleased.
Joshua sends spies into Ai (pronounced "eye") and they report that just a small contingent of men should be able to halt the people of Ai.
So Joshua sends a measly three thousand men to tackle Ai. Looks like the spies didn't really do their job, though, and thirty six soldiers are slaughtered while the rest flee.
As the men of Ai rejoice, the people of Shmoop wonder what happened that three thousand men fled after thirty six died. Did the Cylons show up?
We learn "the hearts of the people melted and turned to water" (5).
Upon hearing the news of defeat, Joshua tears his clothes in true manly style (we don't really know what that means), prays before the Ark, and puts dust on his head along with the elders.
In case you were wondering, this is a traditional expression of grief.
It also gives you a reason to shower, which usually makes you feel better.
Joshua asks God why He had the Israelites come to Canaan just to die.
God answers by telling him to stand up and be a man.
He also mentions that someone didn't obey the herem.
The next morning, Joshua discovers, through a very careful process of guessing, that Achan is the reason why Israel has sinned.
Achan confesses like a champ and is brought with all his possessions and sons and daughters, both stolen and rightfully owned, to the Valley of Achor.
The Israelites then stone them all to death and burn them along with their possessions.
God is now satisfied and the herem is completed.