Thought from Today’s Old Testament Passage:
That Jephthah actually sacrificed his daughter, tragic as that would be, seems the most natural reading of the text. If Jephthah's "sacrifice" of his daughter meant relegating her to a life of perpetual virginity and service at the temple, not one word in the text says so. The only possible support is the comment that whoever comes out of the house "will be the Lord's" (v. 31). But the statement immediately after this proves he had a whole burnt offering in mind—"sacrifice… as a burnt offering."
There is one other problem with the dedication to the temple view. Why didn't Jephthah pay the monetary substitute set forth in Leviticus 27:1-8 in order to gain the release of his daughter? After all, it bothered him that she would be childless and his line and name would fall out of the rosters of Israel. A woman could be redeemed for thirty shekels of silver (Lev. 27:4),if need be.…
The tragedy of Jephthah’s foolish and autocratic vow stands as a reminder to the perverseness of human wisdom when we fail to depend on the living God. In no way should we make Jephthah’s action normative for other believers who also have made foolish vows in the past and feel that now they must stick to their guns, as it were, because the Bible says Jephthah stuck to his vow. Just because something is described in Scripture does not mean God prescribes us to follow it.
(Walter C. Kaiser, Jr., Hard Sayings of the Old Testament (Downer’s Grove, IL: InterVarsity Press, 1988), pp. 104-105)