Charles Ellicott Commentary Judges 11:29

"Then the Spirit of Jehovah 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." — Judges 11:29 (ASV)

He passed over Gilead and Manasseh. —Rather, he went through (Vulgate, circuiens). His object clearly was to collect levies and rouse the tribes—“He swept through the land from end to end to kindle the torch of war and raise the population” (Ewald).

Passed over Mizpeh. —Perhaps, as in the next clause, to Mizpeh.

Passed over to the children of Ammon. — i.e., he went to attack them.