You shall observe the [Feast of] Unleavened Bread, for on this very day I brought your ranks out of the land of Egypt; you shall observe this day throughout the ages as an institution for all time.
Rava reconsidered and then said: It is not only permitted to soak the grains; it is actually a mitzva to soak them, as it is stated: โAnd you shall guard the matzotโ (Exodus 12:17). The Gemara explains this statement: If it is not the case that grain requires soaking, for what purpose is guarding necessary? If you claim that this verse is referring to guarding when kneading, that cannot be the case, as guarding grain while kneading is not considered guarding. If one failed to protect the wheat from becoming leavened up to that point, it is of no use to be careful while kneading it. Consequently, this mitzva to guard the dough cannot be referring to the kneading stage.
It is good to make the mitzvah-matzah from wheat that has been guarded so that no water has fallen on it from the time of harvest, or at least from the time since it was ground [into flour]. But in times of duress, it is permitted to buy flour from the marketplace.
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