Only that the generations of the children of Israel might know, to teach them war, at the least such as before knew nothing thereof; No JFB commentary on these verses.
Related Commentaries of Judges 3:2
Judges 3:2-4
2 Only that the generations of the children of Israel might know, to teach them war, at the least such as before knew nothing thereof;
3 Namely, five lords of the Philistines, and all the Canaanites, and the Sidonians, and the Hivites that dwelt in mount Lebanon, from mount Baalhermon unto the entering in of Hamath.
4 And they were to prove Israel by them, to know whether they would hearken unto the commandments of the LORD, which he commanded their fathers by the hand of Moses.