Judges 3:1-2

Amplified Bible

Idolatry Leads to Servitude

3 Now these are the nations which the Lord left [in order] to test Israel by them (that is, all [the people of Israel] who had not [previously] experienced any of the wars in Canaan; ² only in order that the generations of the sons of Israel might be taught war, at least those who had not experienced it previously).