What does Judges 11:8 mean?
Showing how desperate they are for a military leader to fight the Ammonites (Judges 10:17–18; 11:4), the leaders of Gilead have traveled to Tob to recruit Jephthah. He appears to be the only viable option, although his skills have come from leading worthless men in criminal activity—and that involvement was the result of Gilead driving him out of his father's home (Judges 11:1–3).Jephthah has pushed back, pointing out that the same society that shunned him now wants his aid. Do they really expect him to come to the rescue now that they're in trouble? To show how serious they are, the elders of Gilead tell Jephthah their offer: if he comes home to lead in battle against the Ammonites, he will be head over all the inhabitants of Gilead. The assumption is that he needs to win for this to be granted, but if he does, he would be the head of the entire territory. The situation resembles the offer made by leaders of Shechem to Abimelech, after the death of Gideon (Judges 9:1–6).
Jephthah is interested, but he wants to be clear about the specifics of this offer (Judges 11:9–11).