Exodus 23:30

I will drive them out little by little ahead of you until you have become numerous and take possession of the land.

Treasury of Scripture Knowledge

By little and little I will drive them out from before thee, until thou be increased, and inherit the land.

by driving out all your enemies before you, as the Lord has said.

the Lord will drive out all these nations before you, and you will drive out nations greater and stronger than you are.

The Lord will deal with them as He did Sihon and Og, the kings of the Amorites, and their land when He destroyed them.

The descendants of Manasseh could not possess these cities, because the Canaanites were determined to stay in this land.

So the Lord gave Israel all the land He had sworn to give their fathers, and they took possession of it and settled there.