Judges 11:29-40

Then the Spirit of the LORD came upon Jephthah, and he passed through Gilead and Manasseh, and passed through Mizpah of Gilead; and from Mizpah of Gilead he advanced toward the people of Ammon. And Jephthah made a vow to the LORD, and said, “If You will indeed deliver the people of Ammon into my hands, then it will be that whatever comes out of the doors of my house to meet me, when I return in peace from the people of Ammon, shall surely be the LORD’s, and I will offer it up as a burnt offering.” So Jephthah advanced toward the people of Ammon to fight against them, and the LORD delivered them into his hands. And he defeated them from Aroer as far as Minnith—twenty cities—and to Abel Keramim, with a very great slaughter. Thus the people of Ammon were subdued before the children of Israel. When Jephthah came to his house at Mizpah, there was his daughter, coming out to meet him with timbrels and dancing; and she was his only child. Besides her he had neither son nor daughter. And it came to pass, when he saw her, that he tore his clothes, and said, “Alas, my daughter! You have brought me very low! You are among those who trouble me! For I have given my word to the LORD, and I cannot go back on it.” So she said to him, “My father, if you have given your word to the LORD, do to me according to what has gone out of your mouth, because the LORD has avenged you of your enemies, the people of Ammon.” Then she said to her father, “Let this thing be done for me: let me alone for two months, that I may go and wander on the mountains and bewail my virginity, my friends and I.” So he said, “Go.” And he sent her away for two months; and she went with her friends, and bewailed her virginity on the mountains. And it was so at the end of two months that she returned to her father, and he carried out his vow with her which he had vowed. She knew no man. And it became a custom in Israel that the daughters of Israel went four days each year to lament the daughter of Jephthah the Gileadite.