In what way were Moshe and Aharon Mo'el (deal falsely) with Hashem and fail to sanctify Him?
Rashi: The Torah means that they caused others to be Mo'el 1 and caused Hashem's Name not to be sanctified by not speaking to the rock and having to therefore strike it twice.
See Sifsei Chachamim citing the Ra'am and the L'vush who prefer the alernative text in Rashi - 'Geramtem Lim'ol Bi' (You caused the people to rebel against Hashem.
What are the implications of "al asher Lo Kidashtem Osi"?
Rashi (in PInchas Bamidbar, 27:13): It implies that, had Moshe and Aharon sanctified Hashem's Name, their time to die would not yet have arrived.
Why does the Pasuk insert the (otherwise superfluous) words "be'Soch B'nei Yisrael"?
Why does the Torah repeat Moshe and Aharon's sin?
Rashi: Refer to Bamidbar, 27:13:3:1*.