10 So the assembly sent twelve thousand fighting men with instructions to go to Jabesh Gilead and put to the sword those living there, including the women and children.
11 “This is what you are to do,” they said. “Kill every male and every woman who is not a virgin.”
12 They found among the people living in Jabesh Gilead four hundred young women who had never slept with a man, and they took them to the camp at Shiloh in Canaan.
20 So they instructed the Benjamites, saying, “Go and hide in the vineyards
21 and watch. When the young women of Shiloh come out to join in the dancing, rush from the vineyards and each of you seize one of them to be your wife.
23 So that is what the Benjamites did. While the young women were dancing, each man caught one and carried her off to be his wife. Then they returned to their inheritance and rebuilt the towns and settled in them.
This is according to the most recent translations. Trust me, the older translations are worse.