What is the significance of "Yizb'chu la'Sheidim Lo Elo'ah"?
What is the significance of "Chadashim mi'Karov Ba'u"?
Rashi: 'Even the Nochrim were not accustomed to them. In fact, when a Nochri would see it, he would label it 'a Jewish god'.
Seforno: Whenever they discovered some form of being of which they had previously been unaware, they would assume that it must have come about via a hitherto unknown deity, which they would promptly proceed to worship.
Da'as Zekenim: It was never called a god until now.
What does "Lo Se'arum Avoseichem" mean"?
Rashi #1 (citing the Sifri): It means that your fathers were not afraid of them
What is "Elohim Lo Yeda'um"?
Da'as Zekenim #1, Hadar Zekenim #1, Rosh #1: [People] did not recognize any benefit in [these idols].
Da'as Zekenim #2, Hadar Zekenim #2, both citing R. Yosef Kara, Rosh #2: Hashem did not 'know' (help) them amidst their afflictions, as opposed to "va'Yeda Elokim", "Yadati Es Mach'ovav" (Shemos 2:5, 3:7).