When the Ammonites made war against Israel, the elders returned to Jephthah and made him their head and military leader. God restores Jephthah by His Grace and we see him return, full of scriptural knowledge and empowered by the Spirit. He negotiated biblically with the Ammonites, and led Gilead (Gilead would be a collective term for the tribes of Reuben, Gad, and half the tribe of Manasseh) against them in battle. Unfortunately, he makes a tragic vow to the Lord that affects his only daughter.
And regardless of your stance on the meaning of the vow, what an impetuousand unnecessary vow to make. The Lord’s spirit was upon Jephthah and God would deliver his people with or without Jephthah or his vows.
Psalm 50 says : “If I were hungry, I would not tell you, for the world and its fullness are mine.Do I eat the flesh of bulls or drink the blood of goats?Offer to God a sacrifice of thanksgiving, and perform your vows to the Most High,and call upon me in the day of trouble; I will deliver you, and you shall glorify me.”
We are called to trust in the Lord and depend wholly upon the Grace of God, not our own abilities. Let us be accountable for every word that comes out of our mouth and lean on a Sovereign God.