This means that the deal between Jephthah and the elders of Gilead was ratified in presence of the Lord. That probably means that the ark of God was in the field at Mizpah (2 Samuel 11:11).
It is difficult not to conclude that like Jephthah’s reference to Lord in Judges 11:9 and the elders’ appeal to him in Judges 11:10, the entire ceremony represents a calculated effort to manipulate the Lord, who is completely silent thus far. Jephthah’s relationship to the Lord seems at best one of manipulation and convenience at this point, as if he is trying to push Israel’s God into a corner.
11 So Jephthah went with the elders of Gilead, and the people made him head and leader over them. And Jephthah spoke all his words before the LORD at Mizpah.