Judges 11:34-39

34When 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.

35And 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.”

36So 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.”

37Then 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.”

38So he said, “Go.” And he sent her away for two months; and she went with her friends, and bewailed her virginity on the mountains.

39And 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