In Judges 11:30-31 , he makes a deal with God: if God will help him defeat the Ammonites, Jephthah will sacrifice the first thing that comes out of his house when he returns home. With God's help, he frees Israel from the Ammonites, and upon his return is greeted by his daughter. When he explains to her the agreement he made, she asks for two months to bemoan her virginity in the hills with her friends. After the two months have elapsed, she returns home and Jephthah sacrifices her as a burnt offering (Judges 11:34-39 ).
According to some scholars, it was shameful for a woman to die childless. Thus, Jephthah's daughter bemoans not the fact that she never had sex, but the fact that she never had any children.
It is not clear whether Judges 11:31 should be translated "whoever" or "whatever" (different modern translations use different words). Perhaps Jephthah expected an animal to wander out of the courtyard.
According to some historians, the Ammonites worshiped the god Molech to whom, according to the Bible, people sacrificed children. Thus, the story of Jephthah's daughter carries a measure of irony: Jepthah frees Israel from people who perform human sacrifice, but only at the cost of performing one himself.
Few, if any, apologists defend Jephthah's actions. Rather, apologists concentrate on showing that this does not reflect poorly on God.
"God did not approve of Jephthah's actions"
In Judges 11:29-30 , God does not speak to Jephthah (or anyone) directly. It can thus be argued that silence does not mean assent, especially if it involves human sacrifice, which God has forbidden.
However, God is not shy about showing his disapproval. Throughout the book of Judges, God sends invaders to punish the Israelites for not worshipping him. In Judges 9:53-57 , God arranges for a woman to kill Abimelech to punish him for killing his seventy brothers.
Furthermore, Judges 11:32 says that after Jephthah offered his bargain, "the LORD delivered [the Ammonites] into his hands". Unless it is argued that this is a figure of speech, this means that God has tacitly accepted the agreement. Furthermore, he could have intervened at any time after Jephthah's daughter came to greet him, as in the story of Abraham and Isaac (Genesis 22:1-18 ).
"The sacrifice was metaphorical"
Some apologists (1, 2) argue that the term "sacrifice" is metaphorical, and that Jephthah was offering to make his daughter a servant at the Tabernacle. The justification for this interpretation revolves around the fact that Jephthah and his daughter are saddened by the sexual implications of the agreement — that she will have no children, that he will have no heir — rather than the fact that a person will die.
For one thing, all of these sad consequences are true whether Jephthah's daughter is killed or whether she lives but remains celibate. More importantly, it ignores the terms of the deal in Judges 11:31 : "I will offer it up for a burnt offering".