The people of Israel ask, Which of all the tribes of Israel did not come up in the assembly to the Lord?
They ask because at this point they conveniently recall another oath they had taken at Mizpah, before the battle against Benjamin. They had vowed to put to death anyone who refused to participate in the battle. But if some Israelites never showed up, they would not have sworn the oath not to give their daughters in marriage to Benjamin. So their daughters would not be out of bounds. They are fair game for the remaining Benjamites. Here may be the solution to our problem,
Israel thinks. Our only question now is, can we discover any absentee clan or town large enough to provide the needed number of women?
5 And the people of Israel said, “Which of all the tribes of Israel did not come up in the assembly to the LORD?” For they had taken a great oath concerning him who did not come up to the LORD to Mizpah, saying, “He shall surely be put to death.”