John Gill Commentary Judges 20:14

"And the children of Benjamin gathered themselves together out of the cities unto Gibeah, to go out to battle against the children of Israel." — Judges 20:14 (ASV)

But the children of Benjamin gathered themselves together out
of the cities unto Gibeah
To protect and defend it against the other tribes, being a city of theirs and where the persons charged with the crime lived; these got together thither out of the several cities of the tribe of Benjamin, as many as could bear arms:

to go out to battle against the children of Israel ;
they neither denied the fact, nor attempted to palliate and excuse it, nor sought for peace but at once betook themselves to arms; which showed not only want of prudence but pride, passion and self-confidence, and that they were sadly depraved in their morals to rise up in defence of such wicked men; and a strange infatuation to expect success against such vastly superior numbers, and in so bad a cause.