Judges 11:36-40

³⁶So she said to him, “My father, you have given your word to the Lord; do to me as you have said, since the Lord has avenged you of your enemies, the sons of Ammon.” ³⁷She said to her father, “Let this thing be done for me; let me alone two months, that I may go to the mountains and weep because of my virginity, I and my companions.” ³⁸Then he said, “Go.” So he sent her away for two months; and she left with her companions, and wept on the mountains because of her virginity. ³⁹At the end of two months she returned to her father, who did to her according to the vow which he had made; and she had no relations with a man. Thus it became a custom in Israel, ⁴⁰that the daughters of Israel went yearly to commemorate the daughter of Jephthah the Gileadite four days in the year.