Exodus 23:30

By little and little I will drive them out from before thee,
&c.] Not the beasts of the field, but the inhabitants of Canaan, who were left partly to keep up the cities and towns, that they might not fall to ruin, and to till the land, that it might not be desolate; and partly to be trials and exercises to the people of Israel, and to prove whether they would serve the Lord or not. Just as the corruptions of human nature remain with the people of God when converted, for the trial and exercise of their graces, and that they may have their dependence not on themselves, but on the grace of God to keep them in his ways, and to preserve them safe to eternal glory; and by completing the work of grace, which is gradually done, they might be made meet for it:

until thou be increased, and inherit the land;
for as their enemies were driven out gradually, by little and little, so they multiplied gradually, until at length they became a sufficient number to fill all the cities and towns in all the nations of Canaan, and take an entire possession of it, as their inheritance given unto them by God.