And so wrote Maimonides (Mishneh Torah, Laws of Chametz and Matzah, Chapter 2, Law 1): "And what is this 'nullification' mentioned in the Torah? It is to nullify the chametz in one's heart, and to consider it as dust, and to place in one's heart that there is no chametz in his possession at all, and that all the chametz in his possession is like dust and like something unnecessary." Here is an accurate translation from his language: 'that there is no chametz in his possession,' and not written: 'that there should not be in his possession,' from the language of being ownerless and removed, as the chametz is still in his possession, but without value, as if it has turned into dust. And this is in order to nullify the law of chametz from it, and thereby it becomes forbidden to see or find it.

According to the words of the earlier authorities, that nullification means that one does not desire the existence of chametz and it is considered as dust in his eyes, the puzzling ruling of Maimonides (Chapter 3, Laws of Chametz and Matzah, Law 6) is clarified, where he wrote: "When one checks for chametz on the eve of the fourteenth [day of Nisan], or on the fourteenth [day of Nisan], or during the festival, he recites a blessing before he begins to check: 'Blessed are You, Lord our God, King of the universe, who has sanctified us with His commandments and commanded us regarding the removal of chametz.' And the explanation that he recites before the check 'regarding the removal of chametz' and does not recite this way before the actual removal, can be said in two ways:

A. That the checking involves searching and finding the chametz in order to burn it, and therefore, it is the preparation and beginning of the mitzvah of nullification through burning, and it turns out that checking is an inseparable part of the actual removal of chametz, and it is proper to recite before it the formula 'regarding the removal of chametz.'

B. According to the words of Rabbi Nissim (Ran) that we brought above, and this is his language, "And it can be said, that biblically one of them is sufficient, meaning, either through checking or through nullification, for checking alone is also beneficial, as we say in the Talmud (Zevachim 7b), 'From where do we derive the lighting of the candle for us? We deduce it from the verses,' hence, checking is also biblical, and whoever checked from the Torah does not need to nullify. Therefore, it is proper to say that checking is necessary so that one does not transgress 'You shall not see it again.'" It turns out that checking itself is a commandment of nullification, as we deduce it from the verses, and it is proper to recite a blessing over it 'regarding the removal of chametz.'