The various opinions as to exactly what Moshe’s cheit in the episode of Mei Meriva was are too numerous for me to count much less analyze, so I will just highlight one of my favorites. Although we regular Joes find our lives governed by the rules of teva, a tzadik or navi whose life is dedicated to the purely spiritual is unencumbered by such boundries. The laws of nature and physics are an expression of G-d’s will; where G-d’s will as represented by the needs of the tzadik conflicts with the usual laws of nature, then the needs of the tzadik win out. The gemara says R’ Chanina ben Dosa did not need oil for his lamp because, “He who said oil should burn can also say vinegar can burn”. Similarly, when R’ Chanina was unaffected by a mortal snakebite because sin kills, not snakebites – do not try this at home, as it only works if you are living on a level like that of R’ Chanina and see all of reality as just ratzon Hashem. R’ Pinchas ben Yair could split a river just like kerias yam suf because a physical river’s normal flow must defer to the tzadik’s mission to do Hashem's bidding. (For more on this theme, see the piece entitled Split the Difference in the KallahMagazine divrei torah archives here). When presented with the challenge of people crying for water, Moshe and Ahron had a tremendous opportunity to teach this lesson to Bnei Yisrael. They could have simply squeezed water from a rock like you or I squeeze an orange because nature obeys the desire of a tzadik. Yet, instead of doing so, Moshe and Ahron retreated to Ohel Moed and waited for Hashem’s response. “Lo he’emantem bi l’hakdisheini” – the failure to instill the belief in the power of the tzadik was a failure of emunah, and that is the reason for the severe punishment meted out.
So where did I get this idea from? Noam Elimelech? Radomsker? Some other chassidishe sefer? Guess again! It's in Sefer haIkkarim 4:22 – take a look!