Exodus 23:27-30

“I will send my terror ahead of you and create panic among all the people whose lands you invade. I will make all your enemies turn and run. I will send terror ahead of you to drive out the Hivites, Canaanites, and Hittites. But I will not drive them out in a single year, because the land would become desolate and the wild animals would multiply and threaten you. I will drive them out a little at a time until your population has increased enough to take possession of the land.