What is "l'Sorah veli'Se'udah"?
Rashi (from Vayikra Rabah 6:6): This is connected to above - will we seek needs of the living from the dead?!
Rashi: This is your answer - we must guard Torah, like it says above "Tzor Te'udah Chasom Torah" (16). Do not believe their words.
Radak: This is a Shevu'ah, like one who says 'b'Torah, so and so will be.'
Malbim: The Torah and Te'udah that the Navi gave to you, like it says above "Tzor Te'udah Chasom Torah" (16).
Why does it say "Im Lo Yomeru ka'Davar ha'Zeh"?
Rashi: When you give this answer, the proper people among [Shevna's entourage] will admit that your words are true.
Radak: Also 'Im Lo' is a Shevu'ah, like "Im Lo Shivisi v'Domamti" (Tehilim 131:2) and similar verses. The ones mentioned above (Radak 19 - this nation) will say so.
Malbim: They (Torah and Te'udah) will say (inform you that this conspiracy is futile).
What is "Ein Lo Shachar"?
Rashi (from Targum Yonasan): Other gods, Ov and Yid'oni, it is not proper to be (Radak 1 - there is no one who is) Meshacher Panav (seek it 2 ).
Rashi (citing a Midrash): The light of morning does not shine for them (idols) - they have eyes, but do not see (Tehilim 115:5) - how can they shine for others?!
Vayikra Rabah (6:6) #1: Your idols do not shine light for you.
Vayikra Rabah (6:6) #2: Your idols do not shine for themselves - how can they shine for you?!
Rashi: Even though there is no reality in Ovos, they are not ashamed to tell you [to seek them]!
Radak: It has no light, i.e. reason. It is a dark matter.