QUESTION: The Gemara says that the Mitzvas Aseh to bring the Korban Pesach overrides the Mitzvas Aseh of "Hashlamah," the requirement to ensure that the afternoon Korban Tamid is the last Korban offered upon the Mizbe'ach each day. The Korban Pesach overrides "Hashlamah" because failure to fulfill the Mitzvah to eat the Korban Pesach is punishable with Kares.

The Gemara adds that since the Korban Pesach overrides the Mitzvah of "Hashlamah," one who is Mechusar Kipurim -- who needs to bring a Korban Kaparah in order to become Tahor and fit to eat from the Korban Pesach -- may bring his Korban Kaparah after the Korban Tamid has been offered.

This Gemara is difficult to understand. Why should one's personal Korban override the Mitzvah of "Hashlamah"? Even though it will enable him to fulfill the Mitzvah to eat the Korban Pesach, that Mitzvah will not be done until later. In order for one Mitzvah to override another, it must be done at the same time at which the other Mitzvah needs to be done. Since one who is Mechusar Kipurim will not fulfill the Mitzvah of the Korban Pesach until after nightfall, why should he be allowed to forgo the Mitzvah of "Hashlamah" and bring his private Korban Kaparah after the Korban Tamid has been offered?

(a) TOSFOS (DH Asi) answers in the name of the RIVA that the Gemara refers to a case in which the person who is Mechusar Kipurim already brought his Korban Pesach before he brought his Korban for Kaparah. However, since he is not fit to eat the Korban Pesach in his present state, he is not considered to have brought the Korban Pesach. At the moment that he slaughters his Korban Kaparah, he becomes fit to eat the Korban Pesach (that he slaughtered already) and he fulfills the Mitzvah of offering the Korban Pesach. Accordingly, at the moment that he becomes fit to eat the Korban Pesach, he fulfills the Mitzvah of offering the Korban Pesach. As the Gemara later (90a) teaches, he is exempt from bringing the Korban Pesach on Pesach Sheni as long as he was fit to eat the Korban Pesach on Pesach Rishon. Even though he does not actually fulfill the Mitzvah to eat the Pesach (the part of the Mitzvah that is punishable with Kares), the Mitzvah of offering the Korban Pesach is considered to be a weightier Mitzvah that the Mitzvas Aseh of "Hashlamah," since it is associated with the Mitzvah to eat the Pesach which is punishable with Kares.

(b) Tosfos cites the RI who answers that in order for a stronger Mitzvas Aseh to be able to override a weaker Mitzvas Aseh, the two acts do not have to be done at the same time. Only when one does a Mitzvas Aseh that overrides a Lo Ta'aseh must they be done at the same time.

HAGA'ON RAV YISRAEL ZEV GUSTMAN zt'l explained that this issue may be based on a more basic question. Why is a Mitzvas Aseh able to override a Lo Ta'aseh? After all, a Lo Ta'aseh, a prohibition, is more severe than a Mitzvas Aseh (Yevamos 8a). There are two approaches to this question in the Rishonim.

RABEINU NISIM GA'ON in Shabbos (133a) explains that the Mitzvas Aseh does not actually override or push away ("Docheh") the Lo Ta'aseh. Rather, in a situation in which a Lo Ta'aseh conflicts with a Mitzvas Aseh, the Torah did not apply the Lo Ta'aseh in the first place. That is, the Torah did not give the commandment to observe the Lo Ta'aseh when it is in conflict with an Aseh. The applicability of the Lo Ta'aseh is contingent upon there being no Aseh that opposes it. If an Aseh opposes it, then the prohibition of the Lo Ta'aseh was never said in the first place.

Accordingly, the condition that the Aseh and Lo Ta'aseh must be done simultaneously in order for the Aseh to be "Docheh" the Lo Ta'aseh actually describes the circumstances under which the Lo Ta'aseh applies. When did the Torah not command the Lo Ta'aseh when it clashes with an Aseh? The Torah did not command the Lo Ta'aseh only when the Lo Ta'aseh is in opposition to an Aseh at the exact moment that the Aseh is being performed. When, however, the Lo Ta'aseh and Aseh are not done at the same time, the Lo Ta'aseh does take effect and it remains in force, because it is stronger than the Aseh which cannot override it. This is the opinion of the RI here.

The RIVA, on the other hand, understands that in every case of "Aseh Docheh Lo Ta'aseh," the Mitzvas Aseh pushes aside the Lo Ta'aseh ("Dechiyah"). This is in contrast to the way Rabeinu Nisim Ga'on explains ("Hutrah"). The Riva maintains that an Aseh is stronger than a Lo Ta'aseh (see RAMBAN to Shemos 20:8), as the MAHARIK (Shoresh 139) writes. The requirement that the Aseh must be done at the same time as the Lo Ta'aseh is merely in order to ensure that the person does not transgress the Aveirah first and then forget to do the Mitzvas Aseh. This applies equally when a strong Aseh overrides a weaker Aseh.

The Riva seems to be consistent with his opinion elsewhere (cited by Tosfos to Chulin 141a), where he writes that when an Aseh is opposed by another Aseh and a Lo Ta'aseh, one is not permitted to transgress the other Aseh and the Lo Ta'aseh in order to perform the first Aseh. However, if, b'Di'eved, one transgressed and performed the Aseh, he is not punished with Malkus for transgressing the Lo Ta'aseh, because the fulfillment of the Aseh overrides the Malkus (see Insights to Pesachim 47:3). This makes sense according to the Riva's opinion that the Aseh is stronger than the Lo Ta'aseh and therefore it overrides it, as the Maharik (ibid.) points out. In contrast, according to Rabeinu Nisim Ga'on, the Torah did command the Lo Ta'aseh in such a situation, and thus it is not pushed aside at all, and one will receive Malkus.