Judges 1:35
But the Amorites would dwell in mount Heres in Aijalon, and in Shaalbim: yet the hand of the house of Joseph prevailed, so that they became tributaries. But the Amorites would dwell in mount Heres in Aijalon, and in Shaalbim: yet the hand of the house of Joseph prevailed, so that they became tributaries.
The Amorites continued to dwell in Mount Heres in Aijalon and in Shaalbim rather than being driven from the country. The hand of the house of Joseph prevailed over them until they were made tributaries, exacting tribute where there should have been dispossession. Power to tax the inhabitants was substituted for the complete removal God had directed.
That remaining presence stands as evidence of Israel's incomplete obedience to the divine command to dispossess the inhabitants of the land. What was left undone was not from lack of strength to prevail, but from stopping short of full compliance with God's direction.