But if you do not drive out the inhabitants of the land

Numbers 33:40-56
They left the mountains of Abarim and camped on the plains of Moab by the Jordan across from Jericho.  There on the plains of Moab they camped along the Jordan from Beth Jeshimoth to Abel Shittim.
But if you do not drive out the inhabitants of the land, those you allow to remain will become barbs(倒鉤) in your eyes and thorns in your sides. They will give you trouble in the land where you will live.  And then I will do to you what I plan to do to them.
Why?
Here record the last stay point of Israelite, they camp near Jericho. ready to fight.
God warned to Israelite before they entered the Canaan, they mist drive out all the inhabitants of the and, destroy all their carved images and their cast idols, and demolish all their high places.
If they didn't do it, God will do to them what God plan to do to Canaanite.
How?
Listen to the word of God, love each other and honor the holy name of the Lord.