What does Judges 21:10 mean?
The Lord had commanded Israel to completely wipe out the Canaanites in the Promised Land (Deuteronomy 7:1–4). This was due to their heinous sins and pagan worship practices (Deuteronomy 12:29–31). Israel mostly failed to fully obey this command. At this point in the era of Judges, however, Israel seems intent on carrying out this command against some of its own people, without any command from the Lord to do so.More directly, Israel is trying to wriggle around the consequences of oaths they took without careful thought, before bringing judgment against Gibeah and Benjamin (Judges 20:11–13). One oath was that they would put to death any peoples that did not send representatives to the assembly of the Lord at Mizpah (Judges 21:5).
Only one such group has been identified: those from Jabesh-gilead, east of the Jordan River. The decision is made to send a military force to annihilate the inhabitants, including the women and the "little ones," meaning children. In and of itself, this is a dark decision. It's made worse that it's yet another slaughter of Israelite people by Israelite people. Unlike the recent fight against Benjamin, this action can't even be justified as a "holy war" against a depraved city (Judges 20:22–28). It's a self-justified moral compromise, intended to solve a problem created by making a hasty oath.