So the LORD left those nations, not driving them out quickly, and he did not give them into the hand of Joshua.
The beginning of this paragraph is only a repetition of what account we had before of the people's good character during the government of Joshua, and of his death and burial (Jos 24:29, Jos 24:30), which comes in here again only to make way for the following account, which this chapter gives, of their degeneracy and apostasy.
Commenting on Judges 2:6-23
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, Jdg 2:22; of which there could have been no...
Jdg 2:23 In consequence of this resolution, the Lord let these tribes (those mentioned in Jdg 3:3) remain at rest, i.e., quietly, in the land, without exterminating them rapidly. The expression מהר, hastily, quickly, i.e., according to the distinct words of the following clause, through and under Joshua, appears strange after what has gone before.