There has been some discussion on whether Jephthah could have backed out of his vow. Whether in favour of1 or opposed to the idea,2,3 interpreters generally appeal to legislation from Leviticus 27:1–8 or the instance of Numbers 21:2–3 as bearing upon the vow. Yet even though it is likely that Jephthah is aware of these passages (his speech in Judges 11:12–28 shows familiarity with Numbers 21:1–35), their relevance is questionable at best: their laws do not have a one-to-one correspondence with Jephthah’s case. More helpful is the thesis of David Janzen, that obedience is better than sacrifice (1 Samuel 15:22). Says Janzen, Obeying is better than sacrifice here because, as in the case of Saul [
1 Samuel 10:8], Jephthah had a direct command from Yhwh—in his case in the form of Deuteronomic law—that obviated the sacrifice. In Dtr’s eyes, when Israel wishes to sacrifice, it has an obligation to do so in a manner that does not, unlike the sacrifices of Saul, the Elides and Jephthah, contradict the will of Yhwh.
4 So whatever Jephthah’s reason for keeping the vow, the Lord did not expect him to fulfill a vow that contravened his law.
Thus, Jephthah is not ignorant of the law, but rather he ignores it. He comes across as an idolater, one who has done what pagan Ammon does instead of what covenant Israel was required to do. If idolatry is a problem at the beginning of the Jephthah narrative (Judges 10:6–16), then that compounds the sinfulness of his deed. In his syncretism he believed that God looked for sacrifice instead of obedience. And so he is left with no more hope for posterity.
39 And at the end of two months, she returned to her father, who did with her according to his vow that he had made. She had never known a man, and it became a custom in Israel