Past failures have a way of discouraging many from pressing on in life. A believer’s failures, however, rather than ending his service or obedience, is motivated by the Spirit of God to humbly and more tightly cling to God and forsake self.

I. A Bribe for God (Judg 11:29-31). Peace by diplomacy was impossible, and the Holy Spirit came upon Jephthah like putting on a coat, empowering him for battle against Ammon (Ps 18:34; 144:1). War wasn’t Jephthah’s idea, but the drive of the Spirit gifting and motivating him for the divine task of deliverance. Note that in each case of the Spirit’s clothing a judge, there is no feeling or sign so the person knew of the Spirit’s presence (Judg 3:10; 6:34; 11:29). In fact, Jephthah proved he didn’t know there was anything different about himself.
In his uncertainty, Jephthah returned to what he did best: negotiating, but this time with God. Just as the elders of Israel offered Jephthah a bribe, so he offered God a bribe to help him. A vow always begins with an “if.” A vow is often an attempt to bargain or manipulate: “If” You give me victory, Lord, I’ll .... Jephthah attempted to bribe God to act on his behalf with his most important asset: his family.
God isn’t motivated by man’s attempts at manipulation; He’s moved by His gracious, merciful, loving, faithful character. He can’t be bought with bribes or works. Modern vows like, If I fast ... if I tithe ... if I pray … if I have enough faith ... then God must … seeks to gain mastery over God by our deeds or words. Our effort makes us God’s god, and He is reduced to a servant by coercion. He responds because we act, not because He loves, is generous, or gracious. Desperation, doubt, and spiritual ignorance often lead to mindless passion, and we say and do foolish, sinful things.
Jephthah didn’t need to vow. He couldn’t add to what God had already promised. In the same way, we can’t add to the Spirit’s work saving or sanctifying us (Gal 3:1-5). God works by grace through His gift to us of faith (Gal 3:6-9).
We carelessly say things about God, but then our actions often betray the depths of our true belief; like Peter’s proclamation of never abandoning Jesus (Mt 26:33-35) followed his abandonment and betrayal (Mt 26:56, 69-75).

II. A Boon for Israel (Judg 11:30-31). The Spirit’s presence on Jephthah gave Israel success against Ammon, not the skills, abilities, or tools of the man. God’s work in us is always of greater importance than our work for Him. Israel’s victory should have been a celebratory centerpiece and end to the story, but Jephthah’s foolish sin became a personal disgrace and national tragedy.

III. A Blight for Jephthah (Judg 11:34-40). When Jephthah returned home from battle, his only child, a daughter, greeted him. He tore his clothes, a traditional Semitic symbol of grief, and then blamed his daughter (Judg 11:35). She respected her father, honored the Lord, and was willing to be sacrificed to the Lord.
Israel knew human sacrifice was an abomination to the Lord (Ex 20:13; Lev 18:21; 20:2-5; Deut 12:29-31; 18:9-10), but knowing right and doing right are two different things. The believer’s greatest struggle is seldom knowing what God says, but obeying what He says.
The story is similar to Abraham offering Isaac (Gen 22), except God command Jephthah to sacrifice (Gen 22:2) nor did God prevent Jephthah from fulfilling his vow (Gen 22:11-14).
Don’t get caught in the controversy of the story. Jephthah sinfully tried to manipulate God, and there was a consequence to his sin. Every human savior is deeply scarred by failure and imperfection, but we delight in Jesus, the God-Man. He lived a perfect life (2 Cor 5:21; 1 Pet 2:22), gave Himself as a perfect sacrifice for sin (Heb 9:23-10:18), and today is the perfect minister to His saints (Heb 4:14-16).