Judges 11:39
And it came to pass at the end of two months, that she returned unto her father, who did with her according to his vow which he had vowed: and she knew no man. And it was a custom in Israel, And it came to pass at the end of two months, that she returned unto her father, who did with her according to his vow which he had vowed: and she knew no man. And it was a custom in Israel,
She returned to her father after two months and he kept his vow by setting her apart for the Lord as one who would never marry, so that she remained a virgin for life. Her going to the mountains to mourn and the sorrow remembered afterward was grief over giving up marriage and motherhood in Israel, not grief over approaching death. Because she was his only child, her lifelong childlessness cut off his hope of descendants and of a household continued through her. The keeping of the vow was not the killing of her as a burnt sacrifice, for such a human offering was a heathen abomination forbidden by the law, which required sacrifice at the appointed altar by the priests of clean beasts only. The account stands as a warning against rash vows that bring suffering on the innocent, while the yearly custom that arose was for the daughters of Israel to honor her obedience and comfort her seclusion.
How the Vow Was Fulfilled
After two months she returned to her father and he did with her according to his vow which he had vowed. He did not kill her as a burnt sacrifice but dedicated her to the Lord as a perpetual virgin. The statement that she knew no man means she never married and remained unmarried for life, having no children. Her dedication was fulfilled by lifelong seclusion and service to God, probably lifelong service at the tabernacle. Her continued virginity was itself how the vow was fulfilled.
Her two months of mourning and the mourning afterward were for her virginity, not for her death. She grieved giving up marriage and motherhood, the hope of becoming a wife and mother in Israel. Her sacrifice was that loss rather than her life. Remaining unmarried and childless ended her father's hope of descendants, since she was his only child and only hope of continuing his line. This included losing the hope that the Messiah might come through his descendants, of founding a household, and of ranking among the mothers of Israel.
She returned and acquiesced in the vow, which was noble, and her childlessness was its sorrowful consequence. The custom in Israel arising from this was a yearly observance in her honor. Israel's daughters for four days each year lamented her, or by the margin talked with her. They visited her to mourn with her and to show sympathy for her seclusion and esteem for her filial obedience.
Why Not Human Sacrifice
Doing with her according to his vow cannot mean that he offered her as a human burnt sacrifice, for such an act stood condemned as a heathen abomination. A yearly commemorative observance honoring such a deed would have conflicted with the law rather than served a theocratic purpose. A lawful burnt offering had to be made at the authorized altar through Levitical priests, and a killing on a secret altar would not have been a sacrifice to the Lord. Only certain clean beasts were accepted for sacrifice, while the firstborn of mankind and of unclean beasts had to be redeemed.
His vow offered two alternatives joined by or, to be the Lord's or to be offered as a burnt offering if the law permitted it. Whatever met him was to be given to God in whatever way circumstances allowed, so an animal fit for sacrifice would have been offered directly. A person covered by a singular vow was to be redeemed according to the priest's estimation, and devoting her by a vow of perpetual virginity was customary in such cases. Since human sacrifice was highly offensive to God, doing with her according to his vow meant setting her apart rather than taking her life.
Two months passed before she returned, giving time for reflection. The priests would have intervened and he could have sought release from his vow. His moral character is grounds to believe he would not commit such a deed after that interval, while allowing that a good person may do wrong impulsively. The vow gave no liberty to perform an unlawful act, because a prior obligation to God precludes the right to make unlawful vows or oaths. The sin is in making an unlawful vow, not in breaking it, and though a man may deem it his duty to fulfill an unrighteous vow, God accepts no action brought to Him that is charged with the murder of other duties.
Warning and Wider Echoes
The account to which the verse belongs stands as an example of a rash oath and its consequences, exposing the folly of making rash vows or promises. It is a sad and sorrowful incident in which unforeseen circumstances turned a rash vow into suffering for an innocent person. In that light it warns against the harm that can come from yielding to social fashion. The vow itself was godless, staking a child on one cast of the dice.
Jephthah was a fighting deliverer who arose to deliver Israel, one of the mighty men of war whom God helped when they kept His statutes. His course gives a pattern for God's people to strike rebellion and treason in His strength. His devoting his daughter according to his vow is the true history from which the heathen story of Iphigenia being sacrificed by her father Agamemnon was taken. In this way occurrences recorded in the Old Testament became the foundation for monstrous stories among the ancients.