Who is "Kulchem"?
Rashi: You who do not heed His Nevi'im's words.
Radak: It is most of you. Some did fear Hashem. He addresses "Asher Halach Chashechim" (10), that he called to them to repent. He said, I know that you will not repent, for you were on a bad path until now.
Malbim: You who seek to search (for problems with) the Navi's words.
What fire do they kindle?
Rashi: Hashem's anger against you. Radak - this is like "Ki Esh Kadchah v'Api" (Devarim 32:22). However, that is Po'el Omed (the action applies only to the subject), and here Kodechei is Po'el Yotzei (it acts on others).
Malbim: You want fire to probe the Navi's words. You could not find good oil and wicks for illumination, so you took dry wood and thorns, which cast sparks on you. Your loss is greater than your gain! (I.e. you do not have true proofs to test the Navi's words, just false axioms. They are like sparks, which do not illuminate; they merely blacken the face of the one who blows them.
What are "Me'azerei Zikos"?
Rashi: They hold Zikos, i.e. sparks that are spewn. This is like Zikukin d'Nur (Chulin 137b).
Radak: They kindle sparks. The matter is repeated in different words.
Radak citing Targum Yonasan: Megaren b'Eshta (He will send fire upon you). This is like Targum Yonasan of "v'Hishlachti Vachem" (Vayikra 26:22) - v'Egarei Bechon.
Malbim: Refer to 50:11:2:2.
Why does it say "Lechu b'Ur Eshchem [uv'Zikos Bi'artem]"?
Rashi: Like your ways, you will be stricken.
Radak: You kindled fire, and that fire will consume you; the sin will eradicate you.
Malbim: Go in the light of your small fire, and investigate and philosophize with your intellect, which is too small to grasp the truth.
Why does it say "mi'Yadi"?
Rashi: This retribution will be to you from Me.
Malbim: I guarantee you that even though you lit a fire, you will not lie secure like one who fears Hashem. Rather, you will lie depressed. You will grope like a blind person amidst doubts, and will have no serenity.
What is the meaning of "l'Ma'atzevah Tishkavun"?
Kesuvos 104a: When a Rasha leaves this world, three groups of damaging angels greet him. One group says "Hashem said to the wicked 'there is no Shalom'"; one says "in sadness you will lie down"; the third says, "descend and lie with the uncircumcised."
Radak: This refers to lying down due to illness or death. I.e. you will not have strength to stand in front of your enemies.
