A Matter Of Resolve
‘The One Who Searches Recites A Berachah’
R. Yehuda states that one who searches for chametz must recite a berachah. The Ran (ad. loc.) explains that although all mitzvos require a berachah, the novelty of R. Yehuda’s teaching is that we do not wait and save the blessing for the burning of the chametz on Erev Pesach, which is the primary component of the mitzvah. Rather, we say it prior to the bedikah since searching marks the beginning of disposing (the biur).
The Gemara concludes that the proper text of the berachah is “al biur chametz” – “Blessed are You, Hashem…who has commanded us regarding destroying chametz.”
‘Al Bedikas Chametz’
The Ran asks: Since the berachah is recited prior to the bedikah, the conclusion of the berachah really should be “al bedikas chametz,” not “al biur chametz.” He answers that since the purpose of the bedikah is the ensuing disposal of the chametz, we speak of biur chametz (cf., Rosh ad. loc.).
The Rambam (Hilchos Berachos 11:15) writes that as soon as a person resolves to search for his chametz with the intent of disposing and nullifying it, he automatically accomplishes bitul, for at that point he presumably deems the chametz worthless. The Rambam thus says that the berachah “al biur chametz” refers not only to the act of searching but also to the act of nullification that takes place when one prepares to search for chametz. Accordingly, the text “al biur chametz” is particularly appropriate because the berachah refers to the bitul that is effected at the time of the berachah.
‘Al Bitul Chametz’
The Beis Yosef (to the Tur, Orach Chayim 432, at the beginning) asks why the conclusion of the berachah is not “al bitul chametz” since, biblically, the mitzvah to dispose of chametz is fulfilled with the act of bitul. He answers that a berachah is only recited on physical acts, not on mere thoughts. Since bitul can be accomplished by thinking and does not require verbalization, we cannot recite a blessing on bitul alone.