Albert Barnes Commentary Judges 12:1

"And the men of Ephraim were gathered together, and passed northward; and they said unto Jephthah, Wherefore passedst thou over to fight against the children of Ammon, and didst not call us to go with thee? we will burn thy house upon thee with fire." — Judges 12:1 (ASV)

Compare the similar complaint of the Ephraimites to Gideon (Judges 8:1), when a civil war was only avoided by Gideon’s wise and patriotic moderation. The overweening pride of Ephraim comes out in both occurrences .

We will burn your house upon you with fire—Compare the fierce threat of the Philistines to Samson’s wife (Judges 14:15), and the yet fiercer execution (Judges 15:6). Burning appears as a mode of capital punishment (Genesis 38:24; Joshua 7:25), and as a mode of desperate warfare (Judges 1:8; Judges 20:48; Joshua 8:8, 19, etc.).