What does Judges 21:7 mean?
First, Israel slaughters nearly the entire tribe of Benjamin (Judges 20:47–48) for defending their city of Gibeah (Judges 20:12–13), whose people were guilty of heinous crimes against the Lord. They seem relieved that several hundred Benjaminites escaped the carnage and were now hiding in nearby caves. They don't want the tribe of Benjamin to become extinct. They don't want the circle of the tribes of Israel to be broken.However, before the fighting with Benjamin began, all eleven tribes took an oath not to marry their daughters to any men of Benjamin. They do not even consider breaking this oath, likely because it was well known the Lord would judge those who broke sacred oaths (Deuteronomy 21:21–23). Since all the Benjaminite women and children have been killed and marrying Canaanite women is also not allowed (Deuteronomy 7:1–5), the survivors of Benjamin have no hope to rebuild their tribe.
As it happens, the leaders of the Israelites have an idea for how they can find genuine Israelite wives for the men of Benjamin without breaking their oath (Judges 21:14).
Judges 21:1–7 finds Israel mourning. After the other eleven tribes raged through the territory in a civil war, only six hundred men survive from the tribe of Benjamin. Cities, animals, women, and children have been wiped out. Beyond that, the Israelites made an unwise oath not to give wives to Benjamin. The people weep and make sacrifices to God, but He remains silent. Israel's leaders investigate which clans did not send anyone to fight in the war. This might give them a way to honor their oath while sparing Benjamin from extinction.
Israel grieves the near extinction of the tribe of Benjamin, though the situation is the result of their own excessive force. Worse, the other eleven tribes vowed not to give wives to Benjamin. To prevent the loss of a tribe, two schemes are enacted. First, the Israelites of Jabesh-gilead are wiped out for not sending anyone to support the civil war; the young women are spared and given as wives to Benjamin. Next, the remaining unmarried men of Benjamin stage an arranged kidnapping to "take" wives they cannot be "given." The book ends with another reminder of Israel's lawlessness in this era.