Judges 21:5-6

5Then the Israelites asked, ‘Which people from Israel's tribes did not join us when we all met together at Mizpah?’ They asked this because they had made a serious promise at Mizpah. They had said, ‘We must punish with death anyone who does not join us here to meet with the Lord.’

6The Israelites were very upset about what had happened to Benjamin's tribe. They said, ‘We have destroyed a whole tribe of Israel. They were our relatives.