How did Nechemyah know that he is a false Navi?
Rashi: He told me to transgress [entering the Heichal] due to fear. 1
Malbim: Initially, he thought that perhaps the Nevu'ah is true. However, his counsel to enter the Heichal contradicts his Nevu'ah that Nechemyah will be king, for if so, his enemies cannot kill him!
It should be permitted for Piku'ach Nefesh! We find that if Goyim surround the Azarah, Kohanim may eat Kodshei Kodoshim in the Heichal (Menachos 8b)! (PF)
What is the meaning of "ha'Nevu'ah Diber Alai"?
Rashi: He said these matters to me in the name of Nevu'ah.
Why does it say "Secharo" (singular, he hired him)?
Rashi: Each of them (Sanvalat and Toviyah) paid him to scare me. Malbim - they paid him for the false Nevu'ah, and the counsel.
Ibn Ezra #1: V'Sanvalat means Oh Sanvalat (one of them hired him). This Perush is primary.
Ibn Ezra #2: Secharo is a name (they gave his wage).
