Judges 11:30-31

11:30 Jephthah made a vow to the Lord, saying, “If you really do hand the Ammonites over to me, 11:31 then whoever is the first to come through the doors of my house to meet me when I return safely from fighting the Ammonites – he will belong to the Lord and I will offer him up as a burnt sacrifice.”

Judges 11:39

11:39 After two months she returned to her father, and he did to her as he had vowed. She died a virgin. Her tragic death gave rise to a custom in Israel.