Jephthah’s Vow

[Judg. 12:30] And Jephthah vowed a vow unto the LORD, and said, If thou shalt without fail deliver the children of Ammon into mine hands,
The focus of the story of Jephthah is not so much on the victory that he won with G-d’s help as on his tragic vow which make the victor a victim. His vow from a troubled heart makes him kin to those in all cultures who make vows. He bargain with G-d, once G-d has carried out his side of the bargain, the one who made the vow must do what has passed his lips (Deut. 23:21, 23).
The second part of Jephthah’s vow was that he promised to sacrifice a human being, a Canaanite practice specifically condemned by Israelite Law. The Laws frequently refer to the Canaanite custom of burning their sons and their daughters in the fire to their idols. This is no routine sacrifice of his firstborn son, Jephthah had no son, and he specifically states that the vow refers to whoever comes forth from the doors of my house.
Whatsoever cometh forth of the doors of my house to meet me - This evidently points not to an animal, for that might have been a dog; which, being unclean, was unfit to be offered; but to a person, and it looks extremely as if he, from the first, contemplated a human sacrifice. Bred up as he had been, beyond the Jordan, where the Israelitish tribes, far from the tabernacle, were looser in their religious sentiments, and living latterly on the borders of a heathen country where such sacrifices were common, it is not improbable that he may have been so ignorant as to imagine that a similar immolation would be acceptable to G-d. His mind, engrossed with the prospect of a contest, on the issue of which the fate of his country depended, might, through the influence of superstition, consider the dedication of the object dearest to him the most likely to ensure success.
Shall surely be the Lord's; and or I will offer it up for a burnt offering . The adoption of the latter particle, which many interpreters suggest, introduces the important alternative, that if it were a person, the dedication would be made to the service of the sanctuary; if a proper animal or thing, it would be offered on the altar.
30-31 and 34:35, 39 Jephthah’s nonbiblical ways of thinking and acting the reader must remember the theme of Judges: Everyone was doing what was right in his or her own eyes. Jephthah was no different. The people hesitated to call him as a judge over the tribes on the east bank (before he was finally named) because his mother was a prostitute and his own brothers had driven him from the family inheritance.
There are three main questions to answer here: All else, as they say in Jewish circles, is commentary.
First exactly what did Jephthah mean by his vow?
Before Jephthah marched out of Mizpah, he solemnly vowed to give G-d whoever came out the door of his house if he returned victorious over the Ammonites. This raises the issue of vows and the problem translating whoever.
Vows are not unbiblical, but there are some dangers to avoid in making them. First, it is best to avoid making vows that will afterwards prove difficult for one’s conscience or ability to carry out (Prov. 20:25; Eccles. 5:2-6).
Second, vows should never be used to purchase favor with G-d as if we could work for G-d’s grace or we could influence G-d to do for us what He would not otherwise do. Instead, our vows should express gratitude for Him for His unmerited favor.
But when a vow has been made, the promise ought to be fulfilled. Oaths or vows which violate a moral law of G-d, should not be kept.
How did he carry it out?
Jephthah actually sacrificed his daughter as a burnt offering. She was a virgin and this point is added to emphasize the tragedy and grief of the events described.
Did G-d condone his actions?
The fact that the young women of Israel go out for four days to commemorate the daughter of Jephthah the Gileadite is not a biblical endorsement of this event. Nor does it say this event was observed throughout all Israel. But even if it were a national holiday, it came about by local or national custom and not by the word of G-d from His prophets or inspired leaders.
The return of the victors was hailed, as usual, by the joyous acclaim of a female band (1 Samuel 18:6), the leader of whom was Jephthah's daughter. The vow was full in his mind, and it is evident that it had not been communicated to anyone; otherwise precautions would doubtless have been taken to place another object at his door. The shriek, and other accompaniments of irrepressible grief, seem to indicate that her life was to be forfeited as a sacrifice; the nature of the sacrifice (which was abhorrent to the character of G-d) and distance from the Tabernacle does not suffice to overturn this view, which the language and whole strain of the narrative plainly support; and although the lapse of two months might be supposed to have afforded time for reflection, and a better sense of his duty, there is but too much reason to conclude that he was impelled to the fulfillment by the dictates of a pious but unenlightened conscience. The moment of glory and honor for the conquering hero is dramatically transformed by the joyful sound of timbres and dance of a welcoming girl coming out of the house. The trap set by the unnecessary, unfaithful, and impatient vow suddenly snapped shut on both father and daughter.
Self-sacrifice, she accepted her father’s interpretation that her life was the cost which had to be paid to secure the restoration of land to her people and leadership to her father. Her attitude, unlike her father’s when he made the vow, was not my will….but your will be done. In Memory of her, the only redeeming feature of the tragic story of Jephthah’s vow is the courageous self-sacrifice of his own daughter. Her own lament on the mountains of Gilead was not only to prepare herself for the death which would cut of her life in the prime of maidenhood, but to mourn the fact that her father would have no descendants to carry on his name and to maintain his inheritance which he had won back from his brothers. Recount or repeat the triumphs of Yahweh and the people of Israel. Unfortunately she has been forgotten by Scripture, which praises the father but makes no mention of the daughter (1 Sam. 12:11; Heb. 11:32).