Judges 11:29-40

Then the Spirit of YAHWEH rushed upon Jephthah and empowered him. He and his men marched through Gilead and Manasseh and returned to Mizpah in Gilead, and from there, he stalked the Ammonites. Jephthah promised YAHWEH: “If you give me victory over the Ammonites, I will offer up to you as a burnt offering the first thing that comes out of my house to greet me when I return in victory. I will sacrifice that one as an offering to you.” So Jephthah crossed the river with his men to fight the Ammonites, and YAHWEH gave him victory. He struck at them from Aroer to the area near Minnith, twenty villages in all, and as far as Abel Keramim. The Israelites brought the Ammonites down to the dust in a great slaughter. When Jephthah arrived home at Mizpah, his daughter came hurrying out of the house to welcome her father home, dancing to the rhythm of tambourines. She was his only child—his one and only. When he realized who had come out, he ripped his cloak and was overcome with grief. He exclaimed, “Oh no! My dearest daughter, you have torn my heart to shreds! Must it be you I offer? I have made a solemn promise to YAHWEH, and I cannot retract it!” She said to him, “My father, you have made a vow to YAHWEH and he has delivered you from your enemies, the Ammonites. Do to me what you promised him you would do. But please grant me one thing. Spare me for two months and let me go with my friends to grieve. Let me be free to wander on the hills and to lament my sad fate.” “Go,” he replied, and he sent her away for two months. She and her friends went into the mountains and grieved because she was going to die unmarried and childless. After two months, she returned to her father, and Jephthah fulfilled his vow to YAHWEH. His daughter died still a virgin. (This was the origin of the custom in Israel that young women would go away each year to grieve and lament for the daughter of Jephthah of Gilead.)