Judges 20:10

20:10 We will take ten of every group of a hundred men from all the tribes of Israel (and a hundred of every group of a thousand, and a thousand of every group of ten thousand) to get supplies for the army. When they arrive in Gibeah of Benjamin they will punish them for the atrocity which they committed in Israel.”

Judges 20:31

20:31 The Benjaminites attacked the army, leaving the city unguarded. They began to strike down their enemy just as they had done before. On the main roads (one leads to Bethel, the other to Gibeah) and in the field, they struck down about thirty Israelites.