The Gemora in Pesachim (42a) tells us that Rav Masna said “We must prepare the water (for baking matzos) with mayim shelanu.” The people misunderstood and assumed that he meant only “my” water (the Rav’s water) is kosher for baking matzos. The next day there was a line outside Rav Masna’s door, with people asking for the Rav’s water.
I once saw a question “Why did the Gemora relate this incident? It seems to only show how unlearned the people in his community were. What lesson can we learn from this?
The answer which I saw is that the Gemora was telling us about the emunas hachachamim that Jews have. If the Rav said that this is the way it has to be done, then the people would unquestionably do it that way.
I would like to add a thought about Pesach in general. There are many minhagim: From scrubbing the walls, to peeling the tomatoes, to not eating things that fell on the floor (even though they were washed off) – all of which seem to have no logical explanation. Why is it that “this night is different from all nights of the whole year” – from kitnios down, we have a plethora of minhagim that we struggle to understand, define and live with. The meforshim tell us that Pesach is the chag of emunah. We state that we believe and live with this belief. Possibly, here on Pesach itself, these minhagim show that our belief and reliance on our chachamim is real, even in things that we don’t understand. This is true to the point that we do things (even the water used for the matzos has myriad restrictions on its permissibility, in what and how to store it) that seem to make no sense.
This Shabbos is called “Shabbos Hagadol.” Why that name was chosen is explained by various commentaries. I would like to suggest that starting from this Shabbos we make “big” our appreciation for our mesora, by making a big deal even out of seemingly insignificant and non-understandable regulations.