Scholars and theologians throughout the ages have wondered, "Did Jephthah really sacrifice his daughter? Or did he dedicate her to God for the rest of her life?" Until the Middle Ages, every commentator of record (even Josephus, Antiquities, 5.7.10) wrote that he actually killed her, but enough evidence exists to suggest that he did not offer her on an altar but made her a lifelong Nazirite, totally dedicated and holy to God (Numbers 6:8).
Jephthah knew the law. He knew that God requires parley before battle to give the opponent a chance to surrender or retreat (Deuteronomy 20:10-12). He knew that vows are sacred promises to be kept (Numbers 30). He also knew the history of Israel's approach to the Promised Land and Moses' negotiations with the kings of Edom, Moab, and the Amorites well enough to make a legal point in his own negotiations (Judges 11:15-27). Obviously, Jephthah knew that human sacrifice is a detestable and hated act to God (Leviticus 18:21; Deuteronomy 12:31).
Not only did Jephthah know it was wrong, the people of Gilead would also have abhorred the practice and were commanded to kill one who did it (Leviticus 20:2-5)! They—especially the priests—would never have been a party to it, nor would the maidens have commemorated it (the Hebrew word translated "lament" in Judges 11:40 is actually "praise," "commemorate" or "rehearse").
Nor was Jephthah an impetuous or rash person. His vow was spoken, not on the eve of battle, but on the march to it. Rather than leaping at the chance to command Gilead's army, he patiently negotiated for a more powerful position. He did not rush into battle with Ammon but recruited and trained an army, negotiating with the enemy all the while. If he remained in character, his vow must have been well considered.
The vow itself has been misunderstood too. His vow is in two parts: whatever comes out of the house "shall surely be the LORD'S and I will offer it up as a burnt offering." Bullinger in the Companion Bible says: "The Hebrew Vav [translated 'and' in the KJV/NKJV] is a connective particle, and is rendered in many different ways. It is also used as a disjunctive, and is often rendered 'or' (or with a negative 'nor')." So Bullinger concludes Jephthah vowed to dedicate to God whoever came out to meet him, or if it were an animal, to offer it as a burnt offering.
This agrees with Jephthah's character. He considered the scenario, decided a human being or an animal could fulfill it, and provided for both circumstances. Another factor is the term "burnt offering" (Hebrew olah), which has no connotation of fire or burning. It literally means "that which goes up," and implies total consumption (as one "consumed in his work") or complete surrender. Thus, even without changing the conjunction, the wording of the vow can technically mean that she was completely devoted to God.
Spinsterhood was almost unknown in the Israelitish culture—a woman's whole life revolved around marriage, family, and children. Thus, as it states specifically, Jephthah's daughter mourned with her friends over her virginity, not her impending death. She knew she would not die but remain a virgin for the rest of her life.
In verse 39, the writer repeats, "She knew no man" immediately after he writes that Jephthah performed the vow. If he had truly sacrificed her, would it not have been better to write, "And she died"? But she did not die! She lived out her life without knowing a man! This is why the maidens of Israel praised her so much! She gave up—sacrificed—the one thing that they prized most highly: their ability to have children.
Also, the words "he carried out his vow with her which he had vowed" show that he had divine approval for his actions. God would not have approved of human sacrifice. If God had not approved, the writer would have written of God's displeasure, as he did with Gideon's making of a golden ephod (Judges 8:27). And certainly it would not have become a tradition of praise, a customary event in Israel, if God was not pleased.
Incidentally, human sacrifice, though known among the pagans, was not introduced to Israel until the reign of Manasseh of Judah (c. 697-642 BC). Jephthah began judging about 1096 BC. When the king of Moab sacrificed his son on the walls of his city during a combined siege by Israel, Judah, and Edom in about 850 BC, the Israelites were so repulsed that they immediately lifted the siege and went home (II Kings 3:27).
Richard T. Ritenbaugh
Jephthah's Vow: Did He or Didn't He?