Judges 12:2

(2) I and my people were at great strife with the children of Ammon.—Literally, I was a man of strife, I and my people, and the children of Ammon exceedingly. We have a similar phrase in Jeremiah 15:10. Jephthah adopts the tone of a recognised chief, as he had done to the Ammonites.

And when I called you, ye delivered me not.—Ephraim was not immediately affected by the Ammonite oppression, any more than it had been by the Midianite. The effect of those raids was felt chiefly by Manasseh and by the Eastern tribes. Hence the Ephraimites held themselves selfishly aloof. That we are not told of this previous appeal of the Gileadites to Ephraim illustrates the compression of the narrative. We cannot tell whether it took place before or after the summons of the Gileadites to Jephthah.