Judges 11:29

Then the Spirit of the LORD came upon Jephthah, and he passed over Gilead, and Manasseh, and passed over Mizpeh of Gilead, and from Mizpeh of Gilead he passed over unto the children of Ammon.

Then the Spirit of the Lord came upon Jephthan. The calm wisdom, sagacious fore-thought, and indomitable energy which he was enabled to display, were a pledge to himself, and a convincing evidence to his countrymen, that he was qualified by higher resources than his own for the momentous duties of his office.

He passed over Gilead and Manasseh - the provinces most exposed and in danger for the purpose of He passed over Gilead and Manasseh - the provinces most exposed and in danger, for the purpose of levying troops, and exciting by his presence a widespread interest in the national cause. Returning to the camp at Mizpeh, he thence began his march against the enemy, and there he made his celebrated vow, in accordance with an ancient custom for generals at the outbreak of a war, or on the eve of a battle, to promise the god of their worship a costly oblation, or dedication of some valuable booty, in the event of a victory. Vows were in common practice also among the Israelites. (1 Samuel 1:11; 2 Samuel 15:8, etc.) They were encouraged by the divine approval, as emanating from a spirit of piety and gratitude, and rules laid down in the law for regulating the performance. But it is difficult to bring Jephthah's vow within the legitimate range (see the note at Leviticus 27:28).