See: Judges 11:30-31
After a crushing defeat of the Ammonites, Jephthah returned to his own house, and the first to welcome him was his own daughter. This was a terrible blow to the victor, and in his despair he cried out,
“Alas, my daughter! thou hast brought me very low… I have opened my mouth unto the Lord, and cannot go back.”
With singular nobleness of spirit she answered,
“Do to me according to that which hath proceeded out of thy mouth.”
She only asked two months to bewail her maidenhood with her companions upon the mountains. She utters no reproach against her father's rashness, and is content to yield her life since her father has returned a conqueror.
But was it so? Did Jephthah offer up his daughter as a “burnt-offering”? This question has been much debated, and there are many able commentators who argue that such a sacrifice was actually offered. We are constrained, however, by a consideration of Jephthah's known piety as a true worshipper of Jehovah, his evident acquaintance with the law of Moses, to which such sacrifices were abhorrent (Leviticus 18:21; 20:2-5; Deuteronomy 12:31), and the place he holds in the roll of the heroes of the faith in the Epistle to the Hebrews (11:32), to conclude that she was only doomed to a life of perpetual celibacy.