1 But the Israelites were unfaithful in regard to the devoted things; …
3 When they returned to Joshua, they said, “Not all the army will have to go up against Ai. Send two or three thousand men to take it and do not weary the whole army, for only a few people live there.”
2 Now Joshua sent men from Jericho to Ai, …and told them, “Go up and spy out the region.” So the men went up and spied out Ai.
3 When they returned to Joshua, they said, “Not all the army will have to go up against Ai. Send two or three thousand men to take it and do not weary the whole army, for only a few people live there.” 4 So about three thousand went up; but they were routed by the men of Ai, … At this the hearts of the people melted in fear and became like water.
10 The LORD said to Joshua, “Stand up! What are you doing down on your face? 11 Israel has sinned; they have violated my covenant, which I commanded them to keep. They have taken some of the devoted things; they have stolen, they have lied, they have put them with their own possessions. 12 That is why the Israelites cannot stand against their enemies; they turn their backs and run because they have been made liable to destruction. I will not be with you anymore unless you destroy whatever among you is devoted to destruction.
Achan replied to Joshua
21 When I saw in the plunder a beautiful robe from Babylonia, two hundred shekels of silver and a bar of gold weighing fifty shekels, I coveted them and took them. They are hidden in the ground inside my tent, with the silver underneath.”
26 Over Achan they heaped up a large pile of rocks, which remains to this day. Then the LORD turned from his fierce anger. Therefore that place has been called the Valley of Achor ever since.
Achan and Ai
Not everyone obeyed the command to surrender Jericho’s spoil. When Joshua sends a few thousand men up one of the passes to take the small settlement of Ai, Israel is defeated.
Joshua, shaken by this, turns to God. God commands Joshua to gather the whole people. Defeat has come because of disobedience; the sin must be purged before Israel will be able to stand against the enemies.