Exodus 23:28-30

23:28 I will send hornets before you that will drive out the Hivite, the Canaanite, and the Hittite before you. 23:29 I will not drive them out before you in one year, lest the land become desolate and the wild animals multiply against you. 23:30 Little by little I will drive them out before you, until you become fruitful and inherit the land.