Judges 2:23

Therefore the Lord left these nations, without driving them out hastily,.... Left them unsubdued, or suffered them to continue among the Israelites, and did not drive them out as he could have done; which was permitted, either that it might be seen and known whether Israel would give into the idolatry of these nations or not, Judges 2:22; of which there could have been no trial, if they and their idols had been utterly destroyed; or because the children of Israel had transgressed the covenant of the Lord, therefore he would drive no more of them out, but leave them to afflict and distress them, and thereby prove and try them, Judges 2:20; both senses may very well stand, but the former seems rather to agree with what follows:

neither delivered he them into the hand of Joshua; having an end to be answered by them, before suggested, namely, to prove and try Israel; and, for a like reason, the indwelling sin and corruptions of God's people are suffered to remain in them, for the trial of their graces, and that the power of God in the support and deliverance of them might appear the more manifest.