Exodus 23:30

I'll drive them out ahead of you little by little until you increase in numbers and possess 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.

expelling all your enemies before you, as the LORD said."

then the LORD will dispossess all these nations before you and you'll dispossess nations that are even greater and stronger than you.

The LORD will do to them just as he did to Sihon and Og, the kings of the Amorites, and to their land when he destroyed them.

The descendants of Manasseh did not take possession of these cities, because the Canaanites predominated in that territory.

So the LORD gave all of the land to Israel that he had promised to give their ancestors, and they took possession and settled there in it.