The Tribe of Benjamin's emblem.
Image from S.S. Teacher Edition: Holy Bible, 1896
Keeping up the Benjamins (Judges, Chapter 21) - Prior to Chapter 20, the Israelites had formed a loose confederation of 12 tribes which were ruled by a council of judges. After the events of Chapter 20 at the Battle of Gibeah, the tribe of Benjamin was decimated because they had tried to either kill, or gangrape, one of the other Israelite men, a Levite. It's not clear whether they wanted to kill or gangrape him, but it sounds similar to the story of Noah and I'm leaning toward gangrape.
Instead, the Benjamite men gangraped the man's concubine. After the gangrape, the Israelite man cut his wife up into pieces and sent the pieces to different parts of the confederation of tribes, and the tribes responded by basically destroying the Benjamins. If you look at a map of the 12 tribes of Israel, the Benjamins (Benjaminites?) were a little smudge right smack in the middle of all the other tribes! Though, they did have the city of Jerusalem within their boundaries.
After the civil war, the remnants of the Benjamites were allowed to live on, but all their women and children had been exterminated. Since none of the Israelites wanted to give their daughters to be wives to the Benjamites, the judges decided to give the Benjamites a parting gift -which was to essentially invade neighboring tribes, annihilate their entire population save for women "who had not lain with man".
And that's what Chapter 21 is all about - the decision and the carrying out of a mission. Invade nearby Jabeshgilead, destroy the population, and take their virgin daughters as wives for the Benjamites.
Again, we are confronted with a stark contrast to what modern day religionists try to portray their God to be - the origin of morality. By far, what we are witnessing in the Old Testament is merely the record-keeping of an ancient culture - a primary source. The OT is valuable in that sense, as it preserves the odd behaviors, superstitions, and hangups of at least one group of our ancient ancestors - those men who lived long ago in the arid lands which we now associate with Israel.
Now, on to the Book of Ruth, which promises to be a mercifully short book.