Judges 11:34-40 - Jephthah's Daughter
34 Then Jephthah came to Mizpeh unto his house. And see, his daughter came out against him, with timbrels and dances, which was his only child: so that beside her he had neither son nor daughter. 35 And when he saw her, he rent his clothes and said, "Alas, my daughter, thou hast made me stoop, and art one of them that trouble me. For I have opened my mouth unto the LORD, and cannot go back."
36 And she said unto him, "My father, if thou have opened thy mouth unto the LORD, then do with me according to that proceeded out of thy mouth, forasmuch as the LORD hath avenged thee of thine enemies the children of Ammon." 37 And she said unto her father, "Do this much for me: let me alone two months that I may go down to the mountains and bewail my virginity with my fellows."
38 And he said, "Go." And so he sent her away two months. And she went with her companions and lamented her maidenhead upon the mountains. 39 And after the two months she turned again unto her father, which did with her according to his vow which he had vowed, and so she knew no man. 40 And it became an ordinance in Israel, year by year, that the daughters of Israel should go and lament the daughter of Jephthah the Gileadite, four days in a year.