Jepthah went with the elders - The elders had chosen him for their head; but, to be valid, this choice must be confirmed by the people; therefore, it is said, the people made him head. But even this did not complete the business; God must be brought in as a party to this transaction; and therefore Jephthah uttered all his words before the Lord - the terms made with the elders and the people on which he had accepted the command of the army; and, being sure of the Divine approbation, he entered on the work with confidence.
Jephthah uttered all his words before the Lord in Mizpeh - This phrase designates the presence of the tabernacle, or the ark, or of the high priest with Urim and Thummim Judges 20:26; Judges 21:2; Joshua 18:8; 1 Samuel 21:7. The high priest waited upon Jephthah with the ephod, and possibly the ark, at his own house (see Judges 20:18 here). A trace of Jephthah‘s claim to unite all Israel under his dominion is found in Judges 12:2, and breathes through his whole message to the king of the Ammonites. See Judges 11:12, Judges 11:15, Judges 11:23, Judges 11:27.