Birchas HaMitzvos

This post has been updated - Feb. 3, 2008

There is a general question as to why some mitzvos get a bracha and some don't. The Rashba in his Shaalos and Teshuvos (Sheilah 18) and the Gra (OC 8:1) in Shulchan Aruch deal with this question. Here are some of the rules they set down:

1. If a mitzvah is done without a maaseh there is no bracha. For example, canceling loans in the shemittah year takes no maaseh, so there is no bracha.

2. If a mitzvah is dependent on others, there is no bracha. For example, the mitzvah of tzedakah is dependent on the poor person accepting the money. The same is true for the mitzvah of lending money.

3. If it is possible to uproot the mitzvah through mechilah, there is no bracha. For example, a parent can be mochel on the mitzvah of kibbud, so the mitzvah of honoring carries no bracha. This condition is very similar to the above condition that the mitzvah is dependent on others. Other mitzvos that may fall under these categories are bikkur cholim, havaas shalom, and nichum aveilim - all of which carry no bracha because there accomplishment depends on the acceptance of the recipient.

4. A mitzvah that only takes place due to an aveirah, carries no bracha. For example, returning stolen property is a mitzvah. However, it only takes place after something has been stolen, which is an aveirah, so there is no bracha. The same would be true for returning interest. Also, divorce, although a mitzvah, has some element of aveirah mixed into it, so there is no bracha. Another example is misas beis din, which we don't make a bracha on because Hashem has rachmanus on His creations.

5. A mitzvah like matnos kehunah gets no bracha because you are really not giving anything to the kohen. We say the kohen is zocheh from shulchan gavoah. However, by pidyon haben there is a bracha because there the bracha is on the hafrasha, not the nesinah.

6. Mitzvos like yibum and chalitza do not get a bracha because they are not the ultimate purpose of the mitzvah. Rather, the ultimate purpose is the piryah v'ribya.

Tnai Batel U'Maaseh Kayam

There is a general rule that if someone does a maaseh with a tnai and doesn't formulate the tnai properly, we say that the tnai is batel and the maaseh is kayam. For example, if one performs a kiddushin under some condition, but doesn't formulate the condition with the proper mishpatei hatnaim (no kefel hatnai etc.), we say the tnai disappears and the kiddushin is chal. The question is, why should this be? If the husband did not want the kiddushin to take effect except under certain circumstances, shouldn't we say that there was no proper daas, and the kiddushin doesn't take effect.

The Shut HaRash (35:9 and 46) says that the entire concept of tnai is a chiddush. The idea that someone can make the challos of a maaseh conditional would never have existed if not for the fact that the torah allowed for it. Therefore, if the tnai is made improperly, the chiddush hasn't been executed, and m'maila the maaseh is chal.

However, the Rashba in Gittin 35b leaves this issue as a question.

I heard an explanation of this as follows (see as well Chazon Ish 50 and 53 in Gittin):

The Rosh holds that before the torah came along one could never have made a tnai in any maaseh. For example, can one imagine a tnai in a maaseh shechita. Likewise, a tnai in any maaseh makes no sense. A maaseh kiddushin should automatically take effect just like a maaseh shechitah.

However, the torah was mechadesh, that in certain areas of halacha this is not the case. One can make a tnai and prevent a maaseh kiddushin from being chal. Thus, if the tnai isn't made properly, the maaseh automatically results in its challos.

However, the Rashba disagrees. He holds that shechita and kiddushin are inherently different. By kiddushin, it isn't so much the maaseh kiddushin, but the daas for kiddushin that creates the challos. Thus, even though one can't create a tnai to stop a challos of shechitah, this isn't true for a maaseh kiddushin, or other maasim where the daas creates the challos. Thus, the chiddush of the torah merely was that if you make a tnai, this is how you should do it. The Rashba was, therefore, left with a difficulty. If the tnai is made improperly, why does that mean the maaseh is automatically chal?

A Mute as a Witness

Tosafos in Gittin 5a mentions that a mute (an ilaim) cannot write down b'fanei nichtav u'b'fanei nichtam. The Ran (3a in dapei harif) argues that there is no problem, because b'fanei nichtav is no better than eidus isha.

The difficulty in the whole discussion comes from a Teshuvas Harivash (382 & 413) that says that there is no psul of mipi ksavam at all when it comes to kiyum shtaros. Yet, even the Rivash does not allow a mute to provide the evidence of b'fanei nichtav!

One way to answer this question is to say like the Ktzos HaChoshen in Siman 46:19 that a mute is actually pasul l'eidus due to mipi ksavam as a psul haguf. In other words, it's not merely that eidus must be spoken, but eidus must be provided by one who can speak. However, the ktzos himself leaves off with a question that, in general, psulei haguf are not a problem by the eidus of b'fanei nichtav. So, why should a mute be pasul?

Perhaps we can distinguish between the nature of the psul haguf. If the issue is one of neemanus (whether we trust the eid), we waive our suspicions when it comes to b'fanei nichtav. However, a mute is pasul because he is not "fit for stating" his eidus. This psul is not based in neemanus, but in his communication of eidus. This type of psul we have no reason to waive by b'fanei nichtav.

Defining Reshus HaRabbim D' Orayssa

[Note: This piece continues the theme of the last post regarding eruvin. For more on this topic see the article by R' Hershel Schachter in The Journal of Halacha and Contemporary Society. Many of the ideas in this piece are lifted from that article.]

In order to be defined as a Reshus HaRabbim D’Orayssa there are conditions that must be met. The more conditions that there are, the harder it will be for us to declare an area as a reshus harabbim d’orayssa and the easier it will be for us to build an eruv in that area. The following is a list of conditions needed to declare an area a reshus harabbim d’orayssa. Some of the conditions are subject to dispute:

1. The area should be owned by the public (Eruvin 59a). For example, even if Rockefeller Center met all the criteria of being a reshus harabbim it still would not be one because it is not public owned.

2. The area should not have a ceiling (OC 345:7).

3. The streets should be more than 16 amos wide (OC 345:7).

4. The area should be accessible at all times (Eruvin 6b).

5. The area should have 600,000 people traversing it. This condition is a dispute between rishonim (see Eruvin 59a). It has generally been assumed for generations that we follow the lenient opinion of Rashi and Tosafos that we require the 600,000 in order to declare an area a Reshus HaRabbim. However, some acharonim (see Mishkanos Yaakov OC 120) question this and prefer to follow the Rambam. They contend that the majority of rishonim are actually on the Rambam's side. The acharonim also argue about how exactly to calculate the 600,000.

6. The street should be mefulash through the entire city. This means it runs straight through the city from end to end. R' Shlomo Kahana reportedly (quoted by R' Kasher in Noam) used this leniency to allow the eruv in Warsaw to remain valid. He argued that there was no street that ran straight through the city from end to end with no curves. R' Moshe Feinstein (OC 140) questions the legitimacy of this leniency.

Here are some factors to consider l'chumra when trying to make an eruv:

1. We hold in general that all highways (derachim me’ir l’ir - see Magen Avraham 345:5) are automatic reshuyos harabbim. This means that even if the highway doesn't fulfill all the conditions, the very fact that it is a highway makes it a reshus harabbim.

2. Rav Moshe (Volume 1 of Iggros Moshe, page 240) makes an argument that all central metropolis areas are automatic reshuyos harabbim. The argument is based on a Rabbeinu Efraim that (based on R' Moshe's understanding) says that Yerushalayim did not have an eruv even though it wasn't a reshus harabbim according to the conditions set out above (because it's doors were locked at night). Why not? Because it was the central Metropolis of the area, where everyone gathered. Based on this R' Moshe argues that Manhattan cannot have an eruv.

Here are some additonal factors l’kula:

Aruch HaShulchan (OC 345:19-24) – In order to be a reshus harabbim the street must be the main street of the city. Nowadays all streets cancel each other out and there is no main street. (See Divrei Malkiel Vol. 3 page 267 where R' Tannenbaum opposes using this leniency.)

Chazon Ish (Hilchos Eruvin Siman 43, see especially Os 7. See also Orchos Chaim Vol. 1 page 139 who quotes earlier poskim who agree with the Chazon Ish.) – Nowadays our buildings and houses actually enclose the streets enough to render the entire city into a reshus hayachid. The Chazon Ish demonstates this with diagrams of how our cities are generally constructed. He also relies on some ideas that others question (see Or HaMizrach Nissan 5741).

Tzuras HaPesach

The building of most eruvin in major cities nowadays relies on the concept of tzuras hapesach (see Eruvin 11b). A tzuras hapesach is basically a doorway frame (two standing up poles and a pole across the top). The first issue regarding tzuras hapesach is what exactly does a tzuras hapesach have the ability to do? The Mishna Berurah (OC 362:10) brings the Pri Megadim who holds that a tzuras hapesach only works on a d'rabbanan level. Meaning, if an area is a reshus harabbim on a d'orayssa level, a tzuras hapesach cannot enclose the area and make it into a reshus hayachid. Only in an area like a karmelis can a tzuras hapesach work to allow carrying because the tzuras hapesach acts as a heker. This would limit the use of tzuras hapesach to areas that are not reshuyos harabbim d'orayssa.

The Chazon Ish (OC 70:13) disputes the Pri Megadim and holds that tzuras hapesach works to enclose an area even on a d'orayssa level. He bases this on fact that the gemara (Eruvin 110) says that one can use a tzuras hapesach to separate a field and thus avoid problems of kilayim. This is a d'orayssa halacha. Thus, the Chazon Ish proves that tzuras hapesach works on a d'orayssa level.

Others (see Minchas Yisrael Eruvin 110) dispute the Chazon Ish and say that tzuras hapesach by kilayim only works to be mafsik - to separate, but not to makif - to enclose an area. For example see the Chiddushim of Rav Chaim on the Rambam Shabbos 16:16 where Rav Chaim explains that a tzuras hapesach has a "din mechitza", but is not a real mechitza. He explains that if all you need is a mechitzos to surround an area or mechitzos to separate one area from another, so tzuras hapesach works. However, if you need a certain shiur of mechitzos (like 3 walls for reshus hayachid or a tefach wall for sukkah) so tzuras hapesach will not be effective. The psak in general seems to follow the Chazon Ish that tzuras hapesach could work to enclose even a reshus harabim d'orayssa, if not for a different problem which we will now explain.

The problem is that there is another rule of "asi rabim um'vatli mechitza" (see Eruvin 22a). This rule says that if the rabbim pass through a mechitza, they can be mevatel the entire shem mechitza. This could seemingly mess up our entire use of tzuras hapesach for eruvin. However, for this we rely on a Maharam M'rotenberg (see Mordechai Eruvin Perek HaDar Siman 510) who paskens that we don't say asu rabbim u'mevatli mechitza by areas that are not reshus harabbim d'orayssa. It is for this reason that we first must define an area as a karmelis, before deciding that we can establish an eruv in that area.

[For more on this topic see an article by R' Hershel Schachter in The Journal of Halacha and Contemporary Society. Much of the information in this piece was taken from that article. Also, note that the term "Eruv" in this article refers to the building of the tzuras hapesach. This is how the term is used in Yiddish, even though in the gemara it refers to the matzos that are later set aside.]

Kinyan HaGuf L'zman

The Ktzos HaChoshen in Simanim 241:4, 257:3, 346:5 discusses the issue of "kinyan haguf l'zman". We generally know of two types of kinyanim on an object. First, a person can own something straightaway. This is a kinyan haguf. It implies full ownership of the object. The second type of ownership is what we call a kinyan peiros. A kinyan peiros means that you don't actually own the object, but you have the right to use it. For example, a person might lease a field in order to work it and keep the produce. He doesn't actually own the field, he has only purchased the right to use the field.

The Ktzos (241:4) discusses the halacha that one is allowed to be yotzei the mitzvah of lulav and esrog with a matanah al m'nas l'hachzir. This halacha states that if someone gives me his esrog on condition that I return it to him after, it is considered good enough ownership as far as being yotzei the mitzvah. The Ktzos quotes a Ritva (1st perek of kiddushin) and a Rosh (in Perek Lulav HaGazul) who both say that the only way that this can work is if the person takes that esrog to fulfill the mitzvah, and is then "re-makneh" the esrog back to the original owner. However, if the original owner says, "I am giving you this esrog and it will automatically go back to me when you finish", both the ritva and the rosh say that this is basically a borrowed esrog and would not be a sufficient kinyan to be yotzei the mitzvah. (We are speaking now about the first day of sukkos when a borrowed esrog is not good.)

The Ktzos disputes these rishonim based on a gemara in Baba Basra 137a that discusses giving an esrog to someone "v'acharecha liploni". The gemara implies that even though the esrog will automatically leave the first guys reshus and go to the next guys, it is still a good enough kinyan to be yotzei.

Based on this the Ktzos is mechadesh the idea of kinyan haguf lizman. He says it is possible to have a kinyan for only a temporary time period and yet the kinyan is still considered to be full ownership. Even though it seems like only a kinyan peiros because you have it only temporarily, halachically that is not the case.

Update 1/14/2008: After looking into the Ktzos a little more I have discovered a few things. First, the Rashbam in the gemara in 137a seems to learn that one can be yotzei daled minim even with a kinyan peiros in the case of acharecha l'ploni. The reason is that if the entire purpose of the kinyan is only to be yotzei daled minim, even kinyan peiros is sufficient. However, the Rashba there is mashma somewhat like the ktzos that the nature of the kinyan in that case is actually more than a regular kinyan peiros, along the lines of the ktzos' chiddush of kinyan haguf l'zman. There is also a Kobetz Shiurim on the sugya that gets into these issues. I also saw brought from the Chazon Ish (Even HaEzer 74:1) that he disagreed with the Ktzos' chiddush of kinyan haguf l'zman, and held that, by defintion, if you only own something temporarily it is a kinyan peiros.

This of course is the pashtus, as this is the definition of kinyan peiros in the first place. Inventing a new concept of kinyan haguf l'zman is a big chiddush in that it undoes what are the already more logical categorizations of kinyanim that already exist.

Making One's Chometz Hefker

Rashi on 4b in Pesachim d"h B'Bitul says that Bittul Chometz is learnt from a gezairas hakasuv of tashbisu. The Ktzos in Siman 273:1 asks, why could Rashi not learn like Tosafos that the bittul chometz works mitaam hefker?

The Ktzos uses a yesod that he uses in a number of other areas that perhaps hefker doesn't work as a "daas makneh", but rather mitaam neder. The idea is that one is not being makneh the item to hefker, but rather is making a neder that he no longer will be using the item. Thus, the Ktzos suggests that even if one were to make the chometz hefker, one would still transgress on baal yeraeh and bal yimatzei. Another place where the Ktzos discusses this yesod is in Siman 211:4.

Interestingly, the Ramban in the beginning of Meseches Pesachim suggests a possibility as well that hefker may not work to avoid the issur of baal yeraeh and baal yimatzei. Again, the same question arises, if the chometz is hefker (and thus not yours), why would you transgress the issur of owning it?

I once heard another answer to this question based on the words of Rav Soloveitchik. The gemara says that chometz is one of the items that isn't really in your reshus on Pesach, but the Torah places it into your reshus to make you transgress the issur (if you didn't properly do bittul or dispose of it). This is referred to in the gemara as "asaan hakasuv k'ilu hu birshuso". One possible explanation of this is that in dinei mamonos the torah places it into your reshus, causing you to transgress the issur. However, another way to explain is that despite the fact that the chometz isn't yours b'dinei mamonos, you still transgress as long as you were "rotzeh b'kiyumo" (you wanted it around) and you weren't "mechazer ulav l'sorfo" (you weren't actively trying to destroy it). This would then be another approach to answer the Ktzos' question. It's not that hefker doesn't remove the chometz from your possession. Rather, despite the fact that it does, it still may not work to remove the issur of baal yeraeh and baal yimatzei.

Dina D'Malchusa Dina

The gemara in several places in shas (Gittin 10b, Baba Kama 113a, Baba Basra 54b, Nedarim 28a) has a statement of Shmuel that "Dina D'Malchusa Dina" - the law of the land is law. Generally, when the gemara refers to this halacha it is a reference to the fact that a government has the ability to tax it's citizens according to halacha. The Poskim do, however, expand this halacha to other areas besides taxation. Based on several sources, the halacha may be expanded to such areas as minting currency, keeping law and order, and even possibly to other areas like the validity of government shtaros. For a nice discussion of the many sources on this issue see Rabbi Hershel Schachter's article on Dina D'Malchusa Dina printed in the Journal of Halacha and Contemporary Society.

In terms of the lomdus behind Dina D'Malchusa Dina, there are various opinions as to what precisely is the source. The gemara in Sanhedrin 20b has another statement of Shmuel that "anything said in the Parshas HaMelech (in Sefer Shmuel), a melech is mutar in that". Basically, Shmuel warns the people of all the powers a king will have over them. According to this opinion in the gemara that parsha in navi is to be taken l'halacha, and a melech as actually permitted to do those things. Tosafos there in Sanhedrin says that this rule is only by a Jewish king over the land of Israel. However, others (see Meiri in Nedarim and the Gra in Choshen Mishpat 369) say that this applies to all governments. If so, the Parshas HaMelech would, in fact, be the source for dina d'malchusa dina.

The Dvar Avraham (1:1) in an essay on Dina D'Malchusa Dina proposes that Dina D'malchusa Dina really stems from the halacha of hefker beis din hefker. The sources for that din are explicit in the gemara in Gittin 36b.

The Ramban (brought in the Magid Mishneh Gezailah 5:13) says that dina d'malchusa dina only applies to old taxes, but not new ones the king imposes. R' Schachter explains that he must hold that dina d'malchusa dina is a hischayvus midaas, the people have knowingly been mechayev themselves in the tax. By new taxes there is no such hischayvus. The Rashbam in Baba Basra 54b also seems along these lines, that the source of the halacha is from the minhagei medinah.

The Ran in Nedarim writes that dina d'malchusa dina stems from the fact that the king can expel his people from his land. It's basically a tax of living in the country. Thus, the Ran writes his famous shitah, that since all Jews are entitled to live in Israel, there is no dina d'malchusa there.

Finally, there is the opinion of the Bais Shmuel that dina d'malchusa dina is only a din midrabbanan.

Mitzvos Laav Lehanos Nitnu

Chaim B. has an interesting post about the concept of mitzvos laav lehanos nitnu. Basically, the issue being dealt with is as follows:

We find that by mitzvos d'oraysah, the Baal Hamaor (daf 7b in Dapei HaRif in Rosh HaShanah)says that mitzvos laav lehanos nitnu applies. This means that even if one is mudar hanaah from someone else, the neder wouldn't apply to mitzvos d'oraysah, because that is not considered hanaah. However, mitzvos d'rabbanan are considered hanaah, so the mudar hanaah would not be allowed to help the other guy to fulfill a mitzvah d'rabbanan.

The question here is that the whole thing is counter-intuitive. If I can't give someone hanaah, wouldn't helping someone fulfill a mitzvah d'oraysah be more hanaah than a mitzvah d'rabbanan? If I'm allowed to help him fulfill a d'oraysah, surely I should be allowed to help him fulfill a d'rabbanan.

Here is the answer that Chaim B. brings from R' Shimon Shkop:

We apply the principle of mitzvos lav l’henos nitnu to mitzvos d’oraysa because the act is inherently defined as a ma’aseh mitzvah. However, a mitzvah derabbanan is not inherently a ma’aseh mitzvah; its performance is just a means to accomplish the goal of obeying Chazal and not violating "lo tasur". Therefore, since the act itself is not a mitvah, the neder is chal.

So, basically, R' Shimon is explaining to us that a mitzvah d'rabbanan is not really an "inherent mitzvah".

Here is the answer Chaim B. quotes from R' Soloveitchik:

RYBS argues that where the Torah labels an act as a mitzvah, it cannot be excluded by a neder because it is by definition not an act of hana’ah. However, by dinim derabbanan, the act itself is not defined by the Torah as a ma’aseh mitzvah and therefore the hana’ah received is considered a direct benefit resulting from the performance.

It seems that the basic answer in both these approaches is that the idea of mitzvos laav lehanos nitnu is not a sevara that a mitzvah is not hanaah. If that were the case, so it should be a kal v'chomer - if a mitzvah d'oraysah's fulfillment is not hanaah, surely fulfilling a d'rabbanan is not.

Rather, the idea of mitzvos laav lehanos nitnu is that it is a din. The din is that if it has a shem mitzvah, so the hanaah is not considered hanaah (at least as far as the din of mudar hanaah).

Now, the way I understand RYBS is rather simply that a mitzvah d'rabbanan has no shem mitzvah on a d'oraysah level. This seems very reasonable. The shem mitzvah is only a shem mitzvah d'rabbanan. M'meilah, the mudar hanaah is assur in this case because on a d'orayssa level there is no shem mitzvah to cause the hanaah not to be considered hanaah.

R' Shimon addition to this seems a bit unnecessary. R' Shimon is adding that a mitzvah d'rabban is not a mitzvah inherently because it "is just a means to accomplish the goal of obeying Chazal and not violating "lo tasur". As if it really would be a maaseh mitvah if not for this philosophical reason behind mitzvos d'rabbanan. Why the need for a philosophical reason? Obviously a mitzvah d'rabbanan is not a maaseh mitzvah on a d'oraysah level. It's by definition. Any thoughts?

Eating a Kzayis in Bliah Achas

The Mishnah Berurah (476:41) writes that l'chatchilah it is preferable to eat the k'zayis matzah on Pesach in one swallowing. I heard that the Chofetz Chaim himself was makpid on this halacha even on Sukkos, to eat the k'zayis of bread in the sukkah in one swallow.

Presumably, the idea is that anytime there is a mitzvah of achilah (achilah always being defined as a k'zayis) it is best to do the mitzvah all in one shot.

I heard a question asked on this: Why not say in all the Seudos of Shabbos that one should eat a k'zayis in one shot?

One possible approach may be to use the lomdus we discussed in our two previous posts. The mitzvah to eat the meals of shabbos is not really a mitzvah of a maaseh achilah per se. It is merely a mitvah of oneg shabbos, accomplished through eating. However, the mitzvah of eating matzah and perhaps eating in the Sukkah (acc. to some rishonim) is a mitzvah specifically of achilah. Therefore the Chofetz Chaim was makpid to eat, in those instances, in one bliah.

This is the suggestion I heard. Perhaps another explanation is that the gemara in Sukkah 27a has a gezairah shaveh between the chiyuv to eat matzah on the 15th of Nissan and the chiyuv to eat in the sukkah on the 15th of tishrei. Perhaps it was this equation that motivated to Chofetz Chaim to be machmir the same chumrah on both days.

Women's Obligation in Seudos Shabbos

There is a machlokes amongst the rishonim as to why women are obligated in the seudos shabbos. Is it not a mitzvas aseh shehazman gerama? In the Sefer HaYashar of Rabbeinu Tam Chelek HaTeshuvos Siman 70:4, Rabbeinu Tam says the reason for their chiyuv is because "af hein hayu b'oso hanes" (they too experienced the miracle [i.e. of the manna]). The Ramban in Shabbos 117b argues that the reason is that in all "maaseh shabbos" men and women are equal. (See the Ran there in Meseches Shabbos who says, "kol sheyeshno b'shamor yeshno b'zachor d'shamor v'zachor b'dibbur echad neemru etc.)

Let us now pose the following question: are women obligated in the mitzvah of oneg shabbos? According to the Ramban, the answer appears to be yes, for men and women are equal in all maaseh shabbos. I heard the following approach in Rabbeinu Tam, however. Rabbeinu Tam, in fact, held that women are not obligated in the mitzvah of oneg shabbos. However, it is clear from the gemara in Pesachim 99b (mentioned in our previous post) that women are, nevertheless, obligated in the meals of shabbos. This is evident from the fact that the gemara had a gezairah on all people, men and women, not to eat on erev shabbos (in order to eat the meals in a preferable manner). Rabbeinu Tam therefore derived from this that the chiyuv of seudos shabbos cannot be part of the chiyuv of oneg shabbos. As we said in the previous post, the Yeraim (R' Eliezer Mimitz) seems to hold this way, that the chiyuv of seudos shabbos is not related to the chiyuv of oneg shabbos. The Yeraim was, in fact, a talmid of Rabbeinu Tam, and this could help explain his shittah.

However, the idea of saying that women are not obligated in oneg shabbos is not so simple because, of course we all know, that women light shabbos candles. That obligation is part of the inyan of kavod shabbos. It would seem logical that if women are obligated in kavod shabbos, they are obligated in oneg, as well.

Seudos Shabbos and Oneg Shabbos

In the previous post we mentioned the Mishna in Pesachim that one should not eat on Erev Pesach. We quoted the Rashbam who explained that the gezairah is part of an inyan of hiddur mitzvah that one should eat the matzah with an appetite. The gemara there brings the opinion of R' Yehuda that this halacha is even true by erev shabbos and erev yom tov (that one should not eat then either).

I heard an interesting exposition of three ways to learn the gemara. The pashtus of the gemara would be to say that the din of not eating on erev pesach and not eating on erev shabbos/yom tov is all the same halacha. However, the Rashbam doesn't say that. Instead of discussing hiddur mitzvah by shabbos/yom tov like he did by Pesach, the Rashbam says that the inyan is one of chavivus. In order that the kiddush and the seudah should be chaviv, one shouldn't eat before them. Why does the Rashbam steer away from the idea of hiddur mitzvah that he proposed by Pesach.

The idea may be that whereas by Pesach there is a maaseh mitzvah to eat matzah. By Shabbos and Yom Tov there is no maaseh mitzvah of eating. Rather, the whole concept of the seudah is an inyan of oneg shabbos. If so, it is the person's individual pleasure that is important, not the specific performance of a maaseh mitzvah of achilah. Therefore, the Rashbam turns to chavivus when discussing Shabbos and Yom Tov.

The idea that the seudos are inyanim of oneg shabbos is clear from the Rambam in Hilchos Shabbos 30:9. The Rambam in Chometz U'Matzeh 6:12 is also clear that the idea not to eat on erev pesach is because of chavivus (against the Rashbam). It could be that the Rambam understood this way because he wanted to learn the gemara k'pshuto, that the din by Shabbos/Yom Tov and the din by Pesach is all one din.

Finally, we can present a possible third shitah as the shitah of the Yeraim. The Yeraim in Siman 92 discusses the mitzvah of the seudos shabbos. In Siman 412 he brings the mitzvah of oneg shabbos. The implication is that they are two separate mitzvos (against the Rambam). Therefore, the Yeraim may hold that by both Pesach and Shabbos and Yom Tov the halacha is a halacha in hiddur mitzvah, as the halacha to eat in both situations is a formalized maaseh mitzvah. The Yeraim may even derive his halacha from this sugya in Pesachim. Once the sugya implied that Pesach and Shabbos/Yom Tov is one, it became clear that the mitzvah to eat on Shabbos is independent of Oneg Shabbos.

Zeh Keli V'Anveihu in the Cheftza or the Maaseh??

The first mishna in arvei pesachim 99b says that near mincha time a person shouldn't eat anything on erev pesach. The Rashbam explains that the idea behind this prohibition is that we want the matza that night to be eaten b'teavon - with appetite. The Rashbam adds that this is "mishum hiddur mitvah". I once heard someone point out the following interesting point on this Rashbam. Generally speaking, hiddur mitzvah (learnt from the pasuk of zeh keli v'anvehu) is reserved for cheftza shel mitzvah. For example, a person should have tallis naeh (a nice tallis), tefillin naeh (nice tefillin) etc. This is the way the din is brought in the gemara. Would we say that this din of hiddur mitzvah applies even to the maaseh mitzvah? Is there a din of hiddur mitzvah even in the performance of the mitzvah?

From this Rashbam it seems that, yes, the din of hiddur mitzvah applies even to the performance of a mitzvah. An even further chiddush you see from this Rashbam is that the chachamim have the power to make a gezairah that "forces" people to do hiddur mitzvah. This is certainly a strange idea that requires explanation. Anybody?