Judges 3:2

3:2 He left those nations simply because he wanted to teach the subsequent generations of Israelites, who had not experienced the earlier battles, how to conduct holy war. ¹ 

¹ tn The Hebrew syntax of v. 2 is difficult. The Hebrew text reads literally, “only in order that the generations of the Israelites might know, to teach them war – only those who formerly did not know them.”