Judges 3:1-4

Now these are the nations which the LORD left, that He might test Israel by them, that is, all who had not known any of the wars in Canaan (this was only so that the generations of the children of Israel might be taught to know war, at least those who had not formerly known it), namely, five lords of the Philistines, all the Canaanites, the Sidonians, and the Hivites who dwelt in Mount Lebanon, from Mount Baal Hermon to the entrance of Hamath. And they were left, that He might test Israel by them, to know whether they would obey the commandments of the LORD, which He had commanded their fathers by the hand of Moses.