Why did Yiftach gather all of Gil'ad?
Malbim: He saw that they were not calmed through his soft words.
What is the meaning of "Ki Amru Pelitei Efrayim Atem Gil'ad b'Soch Efrayim b'Soch Menasheh"?
Rashi citing Targum Yonasan: The lowly people of Efrayim 1 used to disgrace Gil'ad, and say what are you of Gil'ad considered amidst Efrayim and [the rest of] Menasheh?!
Radak: [People of Gil'ad] said 'you are lone people of Efrayim.' Because people of Efrayim used to disgrace Gil'ad, when the latter found lone people of Efrayim going in Gil'ad's land, they would strike them.
Malbim: Efrayim objected to Gil'ad picking the leader, as if they are primary in Yosef. Really, Efrayim is primary, and the part of Menasheh that received their portion with Efrayim west of the Yarden; you in Gil'ad are the remnants (secondary part)!
Radak: The war was only against the lowly people, who are called Pelitei Efrayim. They were shepherds who needed to cross the Yarden to graze their animals in Ever ha'Yarden, which was good pasture. Shepherds are usually the lowliest people. The mass killing was due to sins that Shevet Efrayim did covertly.
