Bible Notes Online - Judges 12 - ESV
Commentary

v1: The men of Ephraim grumbled again, see 8.1. They had left the hard work for others, and then complained that they had not been invited to join in; some people are very difficult to please! There was no reference to Ephraim fighting with Deborah, and they had caused problems for Gideon.

v2: Jephthah's words were clear; 'you didn't come'.

v3: Jephthah had to continue to fight without them, risking his own life for his people.

v4-6: The argument became the first fight between tribes of Israel, and sadly not the last. The Ephraimites had despised the Gileadites, calling them "renegades", because they lived east of the Jordan. See Josh 22.24-25, where an altar was built to prevent just this situation.

The battle turned on the Ephraimites' dialect; see also Mark 14.70, where Peter's dialect was his undoing.

v7: Although Jephthah ruled for only 6 years, he did deliver Israel from many years of suffering. After him, a number of Judges ruled, bringing comparative stability to Israel. There were certainly fewer attacks from outside Israel after his time.

v8-15: Three other judges are listed; Ibzan, Elon, and Abdon. There is no mention of them bringing deliverance for Israel. It seems likely that they each ruled over only part of Israel.

Some of the Judges had many children; Gideon (8.30), Jair (10.4), as well as Ibzan (v9) and Abdon (v13).

The Amalekites till held part of the land of Ephraim. Ephraim had grumbled about not being involved in the warfare, yet they had failed to possess the land allotted to them. We cannot grumble that we do not share in ministry, when we have undisciplined and uncommitted lives.