Why does it say "v'Hayah Lahem Devar Hashem
Radak: They did not want to listen little by little - they stumbled in sin little by little, Midah k'Neged Midah.
Malbim: Even though they do not want to hear Devar Hashem, Devar Hashem will come to them, command after command, warning after warning.
What is the meaning of "Tzav l'Tzav Tzav l'Tzav"?
Rashi: Like their Midah, so will be measured to them. He will decree on them the command of nations that subjugate them for a command 1 , toil for toil.
This is because they said 'what the Nochrim commanded us is more important than the Navi's' (Rashi, 10) (PF).
Why does it say "Kav l'Kav [Kav l'Kav]"?
Rashi: They will get a Kav of punishments corresponding to a Kav of Aveiros - Tikvah (hope) in place of hope. They hope for light, and there is darkness.
What is the meaning of "Ze'er Sham [Ze'er Sham]"?
Rashi: In a short time, this will come upon them, and they will be diminished in the land of their enemies.
Why does it say "Lema'an Yelechu v'Chashelu Achor"?
Radak: When they will intend to go forwards, they will stumble backwards, and their enemies hand will be on them - "they will be broken and trapped."
Malbim: One who goes unaware of a stumbling block in his path, he goes forward. One who knows that there is a stumbling block, and he goes intentionally, he stumbles backwards, for he departs from the good, known path. He is broken without a cure. The verse means that Hashem will send His Nevi'im to [warn] them. This will increase their punishment, for they will be Mezid.
Why does it say "v'Chashelu" and also "v'Nokeshu"?
Malbim: Michshol is a rock [on which people stumble]. Mokesh is via a trap that others intentionally hid for him. Michshol is a metaphor for sinning on his own; Mokesh is a metaphor for sinning via enticers and false Nevi'im.
