Joshua 7:1-3

1But the children of Israel committed a trespass in the devoted thing; for Achan, the son of Carmi, the son of Zabdi, the son of Zerah, of the tribe of Judah, took of the devoted thing: and the anger of Jehovah was kindled against the children of Israel.

2And Joshua sent men from Jericho to Ai, which is beside Beth-aven, on the east side of Beth-el, and spake unto them, saying, Go up and spy out the land. And the men went up and spied out Ai. 3And they returned to Joshua, and said unto him, Let not all the people go up; but let about two or three thousand men go up and smite Ai; make not all the people to toil thither; for they are but few.