Joshua 7:12-13

12This is why the Israelites cannot stand against their enemies. They will turn their backs and run from their enemies, because they have been set apart for destruction. I will no longer be with you unless you remove from among you what is set apart.

13“Go and consecrate the people. Tell them to consecrate themselves for tomorrow, for this is what the Lord, the God of Israel, says: There are things that are set apart among you, Israel. You will not be able to stand against your enemies until you remove what is set apart.