Did they come to fight all of Yehudah?
Rashi (7): Yes.
Radak: No. They came to fight the head of Yehudah - Yerushalayim.
What is the meaning of "u'Nekitzenah"?
Rashi: We will wage war against it.
Radak: We will besiege it, until Yakitzu (they will be distressed) due to us, and will open (surrender) to us.
Malbim: They condescendingly depict Yerushalayim as an abcess full of pus. One punctures it with a Kotz (thorn), cleaves it and removes the pus. This is like 'ha'Mafis Mursa' (Eduyos 2:5).
What is the meaning of "v'Navki'enah Eleinu"?
Rashi, Targum Yonasan: We will make it even with us, like a Bik'ah (valley), which is level. It will be uniform with the 10 tribes, to have one common king.
Radak: [Nekitzenah - refer to 7:6:2:2] or Navki'a (we will cleave) its walls and enter it, and it will be in our control.
Malbim: We will conquer it, and plunder the wealth for us.
Who is "Ben Tav'al"?
Rashi, from Targum Yonasan: A son who is Tov Eleinu (good to us).
Rashi #1: One who is Tov to one who is not good in Kel's eyes.
Rashi #2: In the system of Al-Bam (every letter is switched with the 'opposite' letters of the Aleph Beis, i.e. it is 11 letters before or after it - Aleph to Lamed, Beis to Mem?) [Ben] Tav'al is Ben Ramala 1 (Radak - i.e. Ben Remalyahu).
Radak, Malbim: It is a man of Efrayim whom they wanted to make king in Yerushalayim.
Presumably, this refers to Pekach; there is no source to say that it was a brother. (PF)