The story of Achan represents a common belief in Judaism, that the congregation is responsible for the actions of a single individual. The entire nation was punished for the actions of an individual and the inaction of the nation.
             When Israel conquered Jericho, they captured massive amounts of treasure. G-d said that the treasure was impure and that it was forbidden for anyone to take any of it.
             Achan decided that G-d's warnings didn't matter to him, so he partook of the spoils, stealing a Babylonian garment, a bar of gold, and some silver. Achan then hid the spoils in his tent. This showed the complete ignorance of Achan; he tried to hide something from G-d.
             Thirty-six people were killed when Israel went to war with 'Ay. They were killed because the nation as a whole knew what Achan had done, but they didn't chastise him for it at all. Some commentators insist that the nation actually helped him hide the spoils of war, thereby making the punishment all the more deserved.
             When Joshua learned what had happened, he assembled the nation to conduct a lottery to determine who the perpetrator was. The tribe of Yehuda was chosen, and then he singled out the Zerahite family. When the Zerahite family approached individually, Zabdi was singled out. When the household approached individually, Achan was revealed as the sinner.
             Achan, along with his family and all his possessions, was then led up to the Valley of Achor, where he was stoned for his sins.
             The story of Achan proved a very important point, that a nation of bystanders can be punished for their inaction. That was why thirty-six people died at the battle of 'Ay.
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