Judges 2:23

Therefore the LORD left those nations, without driving them out hastily; neither delivered he them into the hand of Joshua.

The verse stands in the introduction to the book of Judges, made up of chapters 1, 2, and 3:1-6, which shows that Israel had not possessed all of the country. It means the Lord left the remaining nations in the land rather than driving them out hastily or delivering them into the hand of Joshua. This followed Israel's failure to carry out God's instructions.

Joshua had not completed the work of driving them out, and the next generation was meant to continue it, but Israel's disobedience and later apostasy left them vulnerable to those nations. The nations left were the five lords of the Philistines, the Sidonians, and the Hivites. Their continued presence served to test whether Israel would keep the Lord's way in faith and obedience, after the people had forsaken him and turned to the gods of the surrounding peoples, and it exposed those who cherished idolatry.

God left them as blessings in disguise to prove Israel and to teach war to the later generation who had not known all the wars of Canaan. In the same way, God has allowed debts to remain on institutions in order to test and prove modern Israel, teaching those who have lived in ease and never known hard times for the truth to know war through self-denial and self-sacrifice in wiping out the debts.