OPINIONS: The Gemara says that both Rebbi Yehudah and Rebbi Meir maintain that Chametz is prohibited only from the sixth hour and onward on Erev Pesach. The prohibition is based on the Mitzvas Aseh of "Tashbisu" ("destroy Chametz from your homes").

If the Mitzvah of "Tashbisu" takes effect at the sixth hour of Erev Pesach, do the prohibitions of Bal Yera'eh and Bal Yimatzei also take effect at that time?

The Rishonim dispute exactly when the prohibitions of Bal Yera'eh and Bal Yimatzei take effect.

(a) According to RASHI here (DH Bein l'Rebbi Meir) and in Bava Kama (29b, DH mi'Shesh), the RAMBAM (Hilchos Chametz u'Matzah 3:8), and the SEFER HA'CHINUCH (end of Mitzvah #9), the prohibitions of Bal Yera'eh and Bal Yimatzei take effect before Pesach begins, from the sixth hour of the day on Erev Pesach. A person who keeps Chametz in his possession at that time transgresses not only the Mitzvas Aseh of "Tashbisu," but also the Mitzvos Lo Ta'aseh of Bal Yera'eh and Bal Yimatzei for owning Chametz after the sixth hour. This is also the implication of the Yerushalmi (Pesachim 5:4), as the MINCHAS CHINUCH (11:1) mentions.

(b) However, the RA'AVAD (Hilchos Chametz u'Matzah 3:8) writes that the prohibitions of Bal Yera'eh and Bal Yimatzei do not apply until the Yom Tov begins. All of the verses that mention Bal Yera'eh and Bal Yimatzei say, "Shiv'as Yamim" -- "seven days." These words imply that the prohibitions apply only to the actual days of Pesach, and not to the day before Pesach. (The TOSFOS YOM TOV (5:4) points out that the words of Rashi later in Pesachim (63a, DH Chayav) imply that Rashi himself retracts his opinion and sides with the Ra'avad.)

OPINIONS: The Gemara teaches that one who rents a home must perform Bedikas Chametz there only if he takes possession of the key by the fourteenth of Nisan. If he does not receive the key by that date, the owner of the home is responsible to perform Bedikas Chametz. What is the reason for this distinction?

(a) RASHI here and the RASHBAM in Bava Basra (53a, DH v'Hashta) explain that the act of handing over the key is a form of a Kinyan, a binding acquisition. When a person rents a property, he can acquire the lease to the property by merely receiving the key. Since handing over the key is the act that effects the Kinyan, whoever has the key to the house on the fourteenth of Nisan is required to perform the Bedikah.

(b) TOSFOS, RABEINU DAVID (in his first explanation), and the RITVA explain that the person who rents the house does not acquire the lease merely by receiving the key. Nevertheless, if he has either made a real Kinyan on the house, or he has received the key to the house (even though he has not made an actual Kinyan), he is obligated to perform the Bedikah. The reason for this is that once the owner gives the key to the tenant, the owner is simply unable to perform the Bedikah since he cannot get into the house. Therefore, if the tenant either has possession of the house or has the key to it, he must perform the Bedikah. (If the tenant has made a Kinyan but has not received the key, he must perform the Bedikah because he owns the house and can demand the key. If he merely has the key to the house but has not made a Kinyan, he must perform the Bedikah because the owner is unable to enter the house without the key.)

(c) RABEINU CHANANEL, the RAN, TOSFOS RABEINU PERETZ, and RABEINU DAVID (in his second explanation) explain that the tenant must perform the Bedikah only when he has both the key to the house in his hand and he has made a Kinyan. The tenant is not obligated to perform the Bedikah if one of those two conditions is not met.

QUESTION: The Gemara attempts to prove that when the fourteenth of Nisan arrives, every house has a Chazakah that it was checked for Chametz ("Chezkas Baduk"). To prove this, the Gemara cites a Beraisa that says that even women, servants, and children are trusted to testify that a particular house was examined for Chametz. Since the testimony of these individuals is normally not valid, it must be that the house is b'Chezkas Baduk.

How does the Beraisa prove that every house is b'Chezkas Baduk? If every house indeed is b'Chezkas Baduk, then why is testimony necessary at all? Bedikas Chametz should not be necessary even if nobody says that the house was examined, since the house is assumed to have been examined already.

(a) TOSFOS (DH Lav) says that a Chezkas Baduk exempts a house from Bedikas Chametz only when the owner is not in town and it is not possible to inquire of him whether or not he performed the Bedikah. If the owner is in town, however, one may not rely on the Chazakah; he must ask the owner if he did the Bedikah. The Beraisa teaches that if, in such a situation, a woman or child says that the house was examined, then the owner does not have to be asked, for in such a case the testimony of the woman or child together with the Chezkas Baduk is sufficient proof that the house was already examined for Chametz.

(b) TOSFOS suggests further that the Beraisa may mean that one may rely on women or children in a case of "Peh she'Asar Hu ha'Peh she'Hitir" (see Insights to Kesuvos 22:1). In such a case, women or children testify that a particular house was not checked for Chametz, but they add that they themselves checked it. If there is no Chezkas Baduk, then they are certainly not trusted to say that they checked it. If there is a Chezkas Baduk, then they are believed to say that they checked the house, because even if they would have said nothing, the house would have been assumed to have been examined (because of the Chazakah). Now that they said that it was not checked, but that they checked it, they are trusted because of the concept of "Peh she'Asar."

QUESTION: The Gemara says that a child is trusted to testify that a particular house was examined for Chametz. TOSFOS here (DH Himnuhu) and in Kesuvos (28a, DH Elu) asks that the Gemara here seems to contradict the Mishnah in Kesuvos (28a). The Mishnah there implies that a person may not testify, when he is an adult, about something he saw when he was a child, even for a matter that is only d'Rabanan. Why, then, do we trust a child who says that Bedikas Chametz, which is d'Rabanan, was performed in a certain house?

(a) TOSFOS answers that the Rabanan permitted a child to testify only in the case of Bedikas Chametz, since it is in his ability ("b'Yado") to search for Chametz himself. In contrast, in the cases in the Mishnah in Kesuvos, the subject of his testimony is not something that is within his control; it is not "b'Yado."

(b) The RASHBA adds that in the case of Bedikas Chametz, the child says that he searched for Chametz himself. We may trust him when he tells us about something that he did himself, because he is more careful about his own actions.

(c) The RASHBA answers further that Bedikas Chametz is something that is done every year, and it involves everyone. Therefore, a child knows what he is talking about when he testifies that Bedikas Chametz was done (in contrast to testimony about signatures and the like; see REMA, end of YD 127). (See also Insights to Kesuvos 28:2.)