The seven priests bearing the seven trumpets of rams' horns before the ark of Yahweh went on continually, and blew the trumpets: and the armed men went before them; and the rearward came after the ark of Yahweh, [the priests] blowing the trumpets as they went.
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.