Question: "Did Jephthah sacrifice his daughter to the Lord?"
Answer: A judge of Israel, Jephthah, had made a foolish vow to the Lord that if God gave him victory in battle, he would sacrifice whatever first came out of his door when he came home (Judges 11:30-31). Jephthah’s daughter was the first thing to come of out his door when he came home (Judges 11:34). The Bible never specifically tells us whether Jephthah actually sacrificed his daughter as a burnt offering. Judges 11:39 seems to indicate that he did: "He did to her as he had vowed." However, since his daughter was mourning the fact that she would never marry instead of mourning that she was about to die (Judges 11:36-37), this possibly indicates that Jephthah gave her to the tabernacle as a servant instead of sacrificing her.
Whatever the case, God had specifically forbidden offering human sacrifices, so God never would have wanted Jephthah to sacrifice his daughter (Leviticus 20:1-5). Jeremiah 7:31; 19:5; and 32:35 clearly indicate that the idea of human sacrifice has "never even entered God's mind." Jephthah serves as an example for us not to make foolish vows or oaths.