To whom does Himru apply, and against whose spirit?
Rashi: Moshe and Aharon, against Hashem, via saying "Shim'u Na ha'Morim" (Bamidbar 20:10).
Radak citing his father, Malbim: Bnei Yisrael, against Moshe. The pressured him until he said "ha'Min ha'Sela ha'Zeh Notzi" (Bamidbar 20:10).
What is the meaning of "Himru"?
Radak #1: This is like Marah and Maror- embittering. This is like "Moras Ru'ach" (Bereishis 26:35).
Radak #2: This is from the root Meri (rebellion), departing from the command. Moshe and Aharon deviated from Hashem's spirit and word. He told them to speak to the rock (Bamidbar 20:8), and they hit it.
What is the meaning of "va'Yvatei bi'Sfasav"?
Rashi: Hashem swore "Lachen Lo Savi'u Es ha'Kahal ha'Zeh" (Bamidbar 20:12).
Radak citing his father: Moshe and Aharon said "ha'Min ha'Sela ha'Zeh Notzi Lachem Mayim" (Bamidbar 20:10), that you (Bnei Yisrael) will force us. They distanced the miracle, and said 'we cannot, until the One who takes out water will come.' They thought that Hashem's honor will come to the rock first, like it says in Refidim "Hineni Omed Lefanecha Sham Al ha'Tzur b'Chorev 1 " (Shemos 17:6). His honor descended in fire and melted the rock, and it turned into water. Moshe and Aharon thought [and their words implied] that the same will happen now. They sinned, for it would be a bigger Kidush Hashem if the rock gives water without fire coming on it.
Radak: Hashem said that they will not enter the land due to this sin.
Malbim: They caused Moshe to speak improperly. Some say that his mistake was not speaking to the rock, or saying "Shim'u Na ha'Morim", or saying "ha'Min ha'Sela ha'Zeh Notzi Lachem Mayim" "Shim'u Na ha'Morim", which implies Safek, or that Moshe and Aharon (and not Hashem) will do so. Because they angered him, his words would not help.
Radak: "Chorev" is not Har Chorev (Sinai). They were in Refidim! Rather, the rock was very dry.
