Judges 11:10

And the elders of Gilead said unto Jephthah
Assenting to his proposal, and not only giving their word for it, but their oath:

the Lord be witness between us, if we do not so according to thy words;
that is, make him head over them; they appealed to the omniscient God, and called on him to be a witness of their agreement to it, and swore by him they would fulfil it; or if they did not, that the Lord would take vengeance on them for it, and punish the breach of this covenant and oath in some way or another; the Targum of Jonathan is,

``the Word of the Lord be a witness between us''