Judges 3:1

Now these [are] the nations which the Lord left to prove
Israel by them
Which are later mentioned, ( Judges 3:3 Judges 3:5 ) ;

[even] as many [of Israel] as had not known all the wars of Canaan;
those that Joshua, and the people of Israel under him, had with the Canaanites, when they first entered the land and subdued it; being then not born, or so young as not to have knowledge of them, at least not able to bear arms at that time.