Judges 11:30-40

Jephthah made a vow to the LORD and said, “If You will indeed give the Ammonites into my hand, then whatever comes out of the doors of my house to meet me when I return in peace from the Ammonites, it shall be the LORD’S, and I will offer it up as a burnt offering.” Then Jephthah crossed over to the Ammonites to fight with them; and the LORD gave them into his hand. And from Aroer to the entrance of Minnith he struck them, twenty cities, and as far as Abel-keramim (brook by the vineyard), with a very great defeat. So the Ammonites were subdued and humbled before the Israelites. Then Jephthah came to his house at Mizpah, and this is what he saw: his daughter coming out to meet him with tambourines and with dancing. And she was his only child; except for her he had no son or daughter. And when he saw her, he tore his clothes [in grief] and said, “Alas, my daughter! You have brought me great disaster, and you are the cause of ruin to me; for I have made a vow to the LORD, and I cannot take it back.” And she said to him, “My father, you have made a vow to the LORD; do to me as you have vowed, since the LORD has taken vengeance for you on your enemies, the Ammonites.” And she said to her father, “Let this one thing be done for me; let me alone for two months, so that I may go to the mountains and weep over my virginity, I and my companions.” And he said, “Go.” So he sent her away for two months; and she left with her companions, and wept over her virginity on the mountains. At the end of two months she returned to her father, who did to her as he had vowed; and she had no relations with a man. It became a custom in Israel, that the daughters of Israel went yearly to tell the story of the daughter of Jephthah the Gileadite four days in the year.