Born of a prostitute and cast out by his family, Jephthah grew up in a tough and bitter world (Judges 11:13). When the people of his tribe decided to overthrow the Ammonites (who had oppressed them for eighteen years; Judges 10:7-8; Judges 10:17-18), Jephthah was the man they asked to be their leader. Jephthah accepted only after the tribal elders had agreed to his conditions, which were that after he had defeated the enemy, he would remain their leader and rule them as a civil governor (Judges 11:4-10).
Jephthah had sufficient faith to believe that God would give Israel victory (Hebrews 11:32-34). He was, however, only a recently reformed bandit, and he had little knowledge of the character of God or the law of God. By vowing, and then offering, his daughter as a human sacrifice in return for God’s help towards victory, he was following the religion of the false gods whom Israel worshipped (Judges 11:29-40; cf. 2 Kings 3:27). He was certainly not following the teachings of Yahweh (cf. Leviticus 18:21; Deuteronomy 12:31).
When Jephthah attacked the enemy, he did not invite soldiers from the tribe of Ephraim to join in the main battle. The Ephraimites were offended and threatened him with violence. Jephthah responded in typically uncompromising fashion. He launched a furious attack and slaughtered the Ephraimites in thousands (Judges 12:1-6). He then settled down to the civilian rule that he had wanted, but after only six years rule he died (Judges 12:7).