Now Jericho was tightly shut up because of the children of Israel: none went out, and none came in.
One result of moral filth is physical disease. Therefore, the destruction of the Canaanites (in some cases together with their sheep and cattle) ensured the removal of deadly diseases that could have threatened Israel’s existence. The absence of Canaanite religious practices would also be a help to Israel’s religious life and moral well-being.