Judges 11:35

So Jephthah passed over to the children of Ammon to fight against them; and the LORD delivered them into his hand.

He struck them from Aroer until you come to Minnith, even twenty cities, and to Abelcheramim, with a very great slaughter. So the children of Ammon were subdued before the children of Israel.

Jephthah came to Mizpah to his house; and behold, his daughter came out to meet him with tambourines and with dances. She was his only child. Besides her he had neither son nor daughter.

She said to him, “My father, you have opened your mouth to the LORD; do to me according to that which has proceeded out of your mouth, because the LORD has taken vengeance for you on your enemies, even on the children of Ammon.”

Then she said to her father, “Let this thing be done for me. Leave me alone two months, that I may depart and go down on the mountains, and bewail my virginity, I and my companions.”

He said, “Go.” He sent her away for two months; and she departed, she and her companions, and mourned her virginity on the mountains.