1)
Why does it "Al Tarimu Karnechem"? Verse 5 said so!
1.
Radak: The matter is repeated to strengthen it.
2.
Malbim: If you see Resha'im regretting their deeds, it is because I (straightness) am planted in their Nefesh; I chastise them not to act frivolously and raise their horns against Hashem.
2)
What is the meaning of "Tedabru b'Tzavar Asak"?
1.
Radak #1: You haughtily speak strong matters against Hashem with your necks, i.e. mouths. Asak (strong) applies to the speech, and to the necks.
2.
Radak #2: It mentions the neck due to thickness - "Yarutz Elav b'Tzavar ba'Avi Gabei Maginav" (Iyov 15:26). Amidst fatness (great good) they deny Kel - "Shamanta Avisa Kasisa" (Devarim 32:15).
