Tag Archives: עשה דוחה לא תעשה

Pesachim 90-92 The אונן, Korban Pesach, and mourning laws on Purim

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The Mishna at the bottom of daf 90b lists a number of people who despite currently being unfit to eat the קרבן פסח may still be included in a group that the קרבן  is slaughtered for, seeing as they will be fit to eat it in the evening.

This list includes, amongst others, one who is an אונן and a prisoner who has been promised that he will be freed by evening.

Although they may be included in a group, the קרבן  may not be slaughtered for them alone, in case they do not become fit to eat it and the entire קרבן  becomes invalid.

Although the term אונן  is generally used to refer to someone who has lost a relative and still has not buried him, the usage of this term does seem to vary from place to place, and the reference to one over these 3 daf presents an opportunity to begin clarifying the scope, status, and laws of an אונן  as opposed to an אבל  and a regular person.

The term אונן/אנינות  is found in the Chumash itself in  the ודוי מעשרות, the declaration made in the third and sixth year before Pesach verifying that one has separated all his tithes and treated them according to halacha.

One of the phrases in this declaration is “לא אכלתי באוני ממנה” (I never ate from it while I was in my אנינות  –  Devarim 26/14.)

The implication is that it is forbidden to eat one’s Maaser Sheini while one is an אונן (the other tithes are not eaten by the original owner but by the Levi ,the poor, or the Kohain)

What precisely “באוני”  means is not evident from the פסוק,but the Ibn Ezra sees it as synonymous with “אבלי” (my mourning) and connects it to the naming of Binyamin as “בן אוני” (Bereishis 35/18.) and “לחם אונים “ (Hoshea 9/4).

Although the actual word is not used, reference to the day one lost a relative can also be found regarding sacrifices, where Aharon explains  that the reason he did not eat from the inaugural sacrifices we because he had lost his 2 sons that day (Vayikra 10/19)

The Targum Yonatan explains that Aharon made a “kal vachomer” argument to Moshe- If an אונן  is not permitted to eat מעשר שני, how much more so a קרבן חטאת  which has a much greater sanctity.

By making this link, the Targum seems to have made it clear that Aharon had the same status of the אונן  mentioned regarding מעשר שני and that this phrase refers to the day of death, leading us to conclude that אנינות דאורייתא  refers to the day of death, at least prior to the burial, and possibly also afterwards.

In truth, the Gemara (Zevachim 100b) brings a Beraisa which records a debate between Rebbe and Chachamim as to how long אנינות  continues, at least on a rabbinical level/

Rebbe is of the view that it is only until the burial whereas the Chachamim hold that it is the entire day.

The Gemara discusses which day they are talking about, whether it is the day of death or the day of burial, in a case where the two do not coincide.

It argues that it is impossible that Rebbe holds that אנינות  on the day of death ends after the burial even before the day is over, seeing as everyone agrees that the entire day of death is subject to the laws of אנינות  based on the passuk “ואחריתה כיום מר”  (after it is like a bitter day-  Amos 8/10   ) and everyone also holds that the night after the day of death is rabbinically subject to the laws of אנינות.

רב ששית  It then suggests that the dispute is referring to the day of burial and a long discussion ensues.

The Gemara concludes that according to Rebbe, the whole of the day of death is subject to אנינות דאורייתא and the night after, as well as the day and night after burial are subject to אנינות דרבנן.

Returning to our sugya, Rashi explains that the אונן  mentioned in our Mishna who may be included in the group for a קרבן פסח seeing as he will be fit to eat it as night, is referring to one who has not yet buried his death, bringing support from the Gemara in Zevachim.

The Gemara (Pesachim 92b) explains that seeing as אנינות at night (even on the day of death) is only דרבנן, Chazal did not apply their own restrictions in a way that would cause the אונן to miss out on a מצות עשה  whose neglect incurs the penalty of כרת.

In contrast, other קרבנות  may not be eaten at night during אנינות דרבנן as Chazal upheld their restrictions even in cases where the אונן  would miss out on a regular מצות עשה , so long as its neglect  does not incur the penalty of כרת .

This requires further explanation- After all, the Gemara (Moed Katan 14b)  rules that אבלות  does not apply on Chol haMoed seeing as the עשה דרבים  (public positive mitzva) of שמחת יום טוב  pushes aside the עשה דיחיד  of אבלות.

The usage of the term עשה indicates that this is referring to אבלות דאורייתא, in other words, אנינות on the first day.

If a public positive mitzva of rejoicing on chol hamoed pushes aside אבילות דאורייתא , why shouldn’t the mitzva of eating any קרבן, particularly public ones, push aside אנינות דרבנן?

Furthermore, surely the rule of עשה דוחה לא תעשה  should allow the mitzva of eating a korban to push aside even a biblical prohibition of אנינות ?

The solution to the later question seems rather straight-forward:

When one action consists of 2 independent results, one a mitzva and one an aveira, the above rule might tell us that the action is defined as a mitzva and not an aveira.

However in the case of the prohibition of eating מעשר שני  or קדשים  during אנינות, the very essence of the prohibition forbids performing the עשה.

From the fact that the Torah forbids eating קדשים    during אנינות , it is clear that the rule of עשה דוחה לא תעשה  cannot apply here anymore than it would apply to any of the other prohibitions regarding eating them, such as doing so when impure.

It could  follow that when Chazal extend such prohibitions, they do so under the same parameters as the original biblical prohibition and unless they specifically say otherwise, the fact that their decree is stopping the fulfillment of an עשה דאורייתא  is irrelevant- that is the essence of the גזירה  , just like it is with גזירה דרבה  which stops us from fulfilling the מצוות עשה  of shofar and lulav and the מצוה מדברי סופרים  of קריאת המגילה  on shabbos, by way of Chazal’s authority to require one to be שב ואל תעשה  (passive) rather than perform a מצוה עשה under circumstances that concern them.

In contrast, when it comes to the laws of אבילות other than those relating to מעשר שני  and קדשים, there is no specific עשה  or גזירה דרבנן  to mourn on Yom-Tov.

The requirement is to mourn during the specified mourning period, and it conflicts with another requirement to rejoice on the festivals – as such, the public requirement to rejoice on the festivals overrides the private requirement to mourn.

Similarly, there is no specific prohibition to eat the קרבן פסח  while one is an אונן- the prohibition only follows from the general prohibition of eating קדשים, and whereas on the day of death when this prohibition is דאורייתא , the fact that eating it is an עשה שיש בו כרת  might not be sufficient to override the prohibition, it is enough for Chazal to choose not to extend this prohibition if it will stop one performing such a serious mitzva.

We should also note that the 2 sources in the Torah for the laws of אנינות  are limited not only to the day of death, but also to a prohibition against eating מעשר שני  and קדשים.

A different area of the laws of אנינות  relates to exemption from performing מצות, but other than not wearing Tefillin which might be a law of mourning itself, this seems to be dependant on whether one is in fact busy with the burial arrangements, and the main sugya on this can be found at the beginning of the third chapter of Brachos (18a.)

A third area relates to the various laws practiced as an expression of mourning, at least on the day of death. These  might be an extension of the prohibition of eating מעשר שני  or קדשים  , either on a  biblical or rabbinical level, but might also be completely non-related, on either level.

This could have major ramifications for whether the law of אבלות  , particularly on the day of death, apply on Purim or not.

If we follow the ruling of the Rambam )Aveil 1/1) who holds that the requirement to keep certain signs of mourning on the day of death is indeed part of the law of אנינות דאורייתא, then it is unlikely that מצוה מדברי סופרים such as rejoicing on Purim, will override this .

On the other hand, if we follow other Rishonim who hold that the laws of aveilus are only rabbinical in status, it is more likely that the higher status of Simchas Purim as a מצוה מדי סופרים  AND a מצוה דרבים  will override them.

The resolution of this question is way beyond the scope of this post, but it is indeed a matter of debate between the Mechaber and the Rema in Orach Chaim whether public mourning applies on Purim or not! (O.C. 696/4 but compare Y.D. 401/7 where the Mechaber seems to agree with the Rema that it does not.)- Perhaps the law of הלכה כדברי המיקל בערוב  should apply?!

These posts are intended to raise issues and stimulate further research and discussion on contemporary topics related to the daf. They are not intended as psak halacha.

Pesachim 83-84 בסיס לדבר האסור בנותר and עשה דוחה לא תעשה

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I would like to have a brief look at some general principles in halacha which are referenced over these two dapim.

One of them is  a principle we generally see in the laws of מוקצה  on shabbos, but which has a surprising application in the laws of the קרבן פסח, possibly opening the door to a broader application of this rule.

The Mishna on daf 83a tells us that the bones, sinews, and נוצר  (leftover meat) of the קרבן פסח  need to be burnt on the 16 of Nissan, the first day of Chol Hamoed, unless the 16’th falls on Shabbos in which case they are burnt on the 17, seeing as we do not burn קדשים  on Yom-Tov or Shabbos.

The Gemara on this Mishna opens by quoting a ruling of רב מרי בר אבוה  in the name of רבי יצחק .

It is forbidden to leave over the meat of the קרבן פסח (or other sacrifices)  until morning, a prohibition known as נותר.

If one transgresses and does so, one needs to burn it on the 16 Nissan, as per the above Mishna.

However this only applies to the meat, not the leftover bones, which usually do not usually require burning.

The חדוש  of רבי יצחק is that if the bones supported leftover meat, they are also forbidden as נותר  and need to be burnt.

The example Rashi gives, based on the continuation of the Gemara, is bones containing marrow.

Seeing as the bones contain or support the marrow which is considered edible meat and subject to the laws of נותר, the bones are considered a בסיס לדבר האסור  (“base for something forbidden”) and also forbidden as נותר  and subject to burning!

It is interesting to analyze whether this law is an extension of the same principle in the laws of shabbos, where a normally non-Muktza item that forms the base or support for a muktza item takes on the forbidden muktza status of the muktza item it is supporting.  (See Shabbos  47a)

Alternatively, it could be that this a different rule sharing only the name, with different mechanics and parameters.

After all, while this rule is generally accepted in hilchos shabbos, the Gemara makes various attempts to prove or disprove it in our context regarding the קרבן פסח but makes no attempt to bring the fact that it applies by הלכות שבת as a support for רבי יצחק.

Furthermore, when it comes to הלכות שבת, the laws of בסיס לדבר האסור  apply also to an item on top of which muktza is placed.

If this was simply an extension of that law, why would Rashi (and the Gemara) bring an example from bones containing marrow- surely bones without marrow but which still have meat connected to them should also have this status? (see Rabbeinu Chananel who indeed explains the Gemara as discussing bones with meat on them!)

If this is indeed an extension of this principle’s application in the laws of shabbos, we also need to investigate whether this is a general rule which extends to other areas of halacha as well.

For example, usually the bones of a non-kosher animal or נבילה being considered inedible are not treated with the same stringency as the meat itself when it comes to the laws of כשרות and might even combine with the kosher meat in  mixture to nullify the non-kosher meat בשישים  (in sixty times the amount-see Y.D. 99/1)

Should this principle be extended to all areas of halacha by default, perhaps when bones contain marrow, (or according to Rabbeinu Chananel if meat is still attached to them) they should be treated with the same stringency as the forbidden meat itself?

In order to answer these questions sufficiently, it is necessary to understand the source, whether פסוקים , מסורת, or סברא   (logic/lomdus) for this rule both regarding shabbos and קדשים and assess whether the source is the same in both cases and whether it also applies to other cases or not.

As muktza is a דין דרבנן  and נותר  is a דין דאורייתא (though the rule of עצמות ששמשו נותר  which designates it as a בסיס  is likely דרבנן ), the first two might be problematic but a common סברא, so long as not contradicted by any counter-examples in the primary sources, might do the trick.

One possible conceptualization of this rule could be that when an item of neutral status supports an item of forbidden status, it loses its independent identity and takes on the nature of the forbidden item it supports, at least on a rabbinical level.

An analogy could be one who supports people’s sinful actions, מסייעין ידי עובדי עבירה, who to a certain extent, and on a rabbinical level only, are also considered sinners. Yet they do not take on the same status as the sinner himself, but only the status of one who transgresses the rabbinical prohibition of assisting sinners.

Yet in both our cases, the item supporting the forbidden item does not just become forbidden but takes on the status of the forbidden item.

This is not necessarily a contradiction as it is possible that a person, being a complex being with his own free choice and דעת  while partly liable for other people’s sins that he enables, does not completely lose his independent status either.

In contrast, an inanimate object which lacks such דעת, has a far weaker level of independence, which is easily completely overridden  by a forbidden object it supports.

 If this is indeed the lomdus, it would not surprise us if this principle applies in other areas of halacha.

However, it is also possible that this principle is only applied by Chazal is certain specific cases and that in other cases, even if the logical principle they based this rule on applies conceptually, they chose for other reasons not to apply it there.

Much more to go into it, but as usual, just raising issues!

Another well known principle referred to at the bottom of 83b and beginning of 84a is the rule of  עשה דוחה לא תעשה  – a positive mitzva pushes aside a negative mitzva. (see my recent post on Pesachim  58-59  )

In our case, we learnt in the Mishna that one may not burn נותר  on Yom Tov and waits till chol hamoed to do so.

The Gemara asks why the mitzva of burning the נותר  does not push aside the prohibition of doing melacha on Yom-Tov based on this principle.

Various answers are given, but the final word goes to Rav Ashi, who explains that in addition to the prohibition of performing melacha on Yom-Tov, there is also a positive mitzva to rest on Yom-Tov, based on it being described as a שבתון (day of rest.)

Similar to shabbos, when one does melacha on Yom-Tov, one not only transgresses a negative commandment but also the positive command of resting.

Although a positive command pushes aside a negative command, it does not push aside a negative command and a positive command.

As such, the rule of עשה דוחה לא תעשה  can never apply to melacha on Yom-Tov, just as it cannot apply on shabbos.

A broader study of the rule of עשה דוחה לא תעשה  , particularly the long sugya in Yevamos, will reveal that one of the potential sources for this rule is the fact that a ברית מילה can be performed on shabbos- despite the fact that performing melacha on Shabbos involves both a positive and negative mitzva.

If this is the case, how does Rav Ashi say with such confidence that an עשה  cannot push aside both a לא תעשה  AND  an עשה ?

Food for thought for next time we encounter this rule!

These posts are intended to raise issues and stimulate further research and discussion on contemporary topics related to the daf. They are not intended as psak halacha.

Pesachim 58-59 When one mitzva clashes with another: עשה דוחה עשה

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In loving memory of our dear friends, Judith Ginsburg and Ian Shapiro of blessed memory, who were both recently taken by the cursed COVID-19 plagues, as well as that pillar of the South Africa and world Jewish community, the great philanthropist and איש חסד, Eric Samson of blessed memory, who passed away yesterday in Los Angeles.

In an all-encompassing field such as halacha, it is inevitable that at times, one value will clash with another, and it is reasonable to assume that the halacha itself provides solutions for such a clash.

One of the rules we have seen is the principle of עשה דוחה לא תעשה  – a positive mitzva pushes aside a negative one  (Yevamos from 3a.)

Although the basis behind this rule requires much analysis, one approach seems to be that when one action involves both a prohibition and a positive mitzva, we define the act based on the positive mitzva and not based on the prohibition.

For example, the act of circumcision when the 8’th day falls on shabbos involves a prohibition against melacha on Shabbos, as well as the mitzva of circumcision, and this rule tells us that the positive mitzva of circumcision pushes aside the prohibition of melacha on shabbos, and the act is performed.

Where a garment is made out of linen and the tzitzit are made out of wool, the same principle tells us that the act of wearing is defined by the positive mitzva of tzitzit and not by the prohibition of wearing shaatnez.

On the other hand, a different principle tells us that the ends does not always  justify the means- for example, one may not fulfil the mitzva of the 4 species on Sukkot if they have been stolen- this would be considered a מצוה הבאה בעבירה  (a mitzva that comes/came   with/through a sin), another rule requiring more precise definition.

On our dapim, we encounter another principle that relates to clashes between mitzvos, this time when one positive mitzva clashes with another.

There is a positive mitzva, known as עשה דהשלמה , which states that the תמיד של בין הערביים  (regular afternoon sacrifice) should be the last sacrifice of the day, with the notable exceptions of the נרות  (evening candles)  the evening קטורת  (incense), and the קרבן פסח  (pesach offering.)

Yet there are times when someone might need to offer a different sacrifice after the afternoon offering has already been made, in order to be declared fit again to eat the קרבן פסח .

For example, a מצורע  (leper) might need to still bring his final offerings that afternoon, without which he would not be permitted to eat his קרבן פסח .

The same might apply to one who needs to eat a קרבן שלמים  (peace offering) that he has brought.

Here, there is no blanket permission to actively be מבטל מצות עשה  (nullify a positive mitzva) in order to actively fulfill another.

Yet there are cases where due to the greater status of the one commandment, the other will take priority.

The Gemara on 59a brings a Beraisa which tells us that a מצורע  (leper) who needs to bring his final sacrifices to clear him to fulfill the command of eating the korban pesach, one of the only two positive mitzvot that one incurs the severe punishment of כרת  for neglecting to perform, the more severe commandment to eat the korban pesach pushes aside the requirement for the regular afternoon sacrifice to be the last non-Pesach sacrifice of the day!

The same Beraisa, however, also gave permission any time to a regular impure person on any evening of the year to bring his outstanding sacrifice after the   תמיד של בין-הערביים in order to be able to eat his קרבן שלמים that needs to be eaten that night!

The Gemara notes that seeing as refraining from eating these sacrifices is not subject to the same severe terms, they should not in and of themselves be enough to push away the עשה דהשלמה.

The Gemara thus qualifies the later permission to be referring to situations where the אסור עשה does not apply, seemingly concluding that only a positive mitzva that involves כרת  if not performed may push aside another positive mitzva (or its related אסור עשה.)

Yet, as mentioned above, there are other times when a positive mitzva pushes aside another one, among them:

  1. The laws of mourning (even the biblical ones on the first day) do not apply on Chol-hamoed, as the obligation to mourn is pushed off by the obligation to rejoice on the festivals, which is an  עשה דרבים  (positive command on the public-Moed Katan 14b.)
  2. The prohibition against freeing an עבד כנעני  (Caananite slave [in the days when slavery was acceptable]) is derived from the positive mitzva of לעולם בהם תעבודו  (you shall work them forever.)   Yet, the Gemara (Brachos 47b) tells us how Rabbi Eliezer freed his slave to make a minyan (Brachos 47b), and that it was not considered a מצוה הבאה בעבירה  because it was for the sake of a מצוה דרבים  (public mitzva.)

We should note that the term עשה דרבים  is not used there, probably because making a minyan is only a rabbinical mitzva, but that we see that even a rabbinical mitzva of the public, however that is defined, might push aside an אסור עשה , at least this particular one.

3. There is a similar case of the חצי עבד חצי בן חורין  (half slave half free person whose owner is compelled to free him so that he can fulfill the mitzva of פרו ורבו  (having children- Gittin 41a) Seeing as the mitzva of פרו ורבו  is based on the idea that the world should not become desolate of people, perhaps this is also considered a מצוה דרבים- see Tosfos and other Rishonim on the above sugyos for further discussion.

There is much to discuss about the rule that a more serious mitzva can push aside a less serious one, but I would like to focus on one issue brought up by the Tosfos.

One of the limitations of the rule of עשה דוחה לא תעשה is that one has to perform the לא תעשה  at the same time as the עשה .

If the לא תעשה  is done before the עשה, then the rule does not apply, its is forbidden, and might also be a מצוה הבאה בעבירה.

This makes sense according to the explanation we brought regarding the dynamics of עשה דוחה לא תעשה.

One can only define an action based on its mitzva component as opposed to its aveira component when they are both components of the same action, forcing one to choose how to define it. In such a case, the Torah teaches us that the mitzva component prevails.

If however,  two different actions are involved, then there is no need to choose, and the initial forbidden action cannot become permitted because of a later different “mitzva” action- here we say that the ends do not justify the means.

Assuming the mechanism whereby a more serious positive mitzva pushes aside a less serious one is similar to that of עשה דוחה לא תעשה, one would expect the same limitation to apply, and in the case of mourning on chol hamoed, it indeed could- one is pushing aside one’s obligation to mourn at precisely the same time that he is fulfilling the mitzva of rejoicing on the festival.

Yet in our case, we see that one may bring a sacrifice after the תמיד של בין בערביים in order that one will later be able to fulfill the mitzva of קרבן פסח, even though these do actions are clearly not at the same time!

Tosfos points out that the same applies in the case of freeing the slave in order to make the minyan (as it does while freeing a slave in order for him to be able to have children.)

In truth, one could have explained the case of the slave differently, saying that the very prohibition of freeing a slave only applies if it is not done for the sake of a mitzva, making it different from other אסורי עשה .

From the fact that Tosfos does not do this, we see that he sees the case of the slave not as an exception but as a precedent for any public mitzva pushing aside an אסור עשה, possibly even a rabbinical one, which would be a tremendous חדוש  requiring further discussion.

In any case, in our case, there is no possibility of such an explanation, and Tosfos concludes that when it comes to situations where we do apply the rule of עשה דוחה עשה, the limitation that the two need to take place simultaneously does not apply. This is because unlike its “sister” principle where a positive mitzva pushes off a negative mitzva which is generally treated as more severe than a positive mitzva, in this case it is the more serious mitzva which is pushing off the less serious one.

It is clear that even if Tosfos would accept the “lomdus” in עשה דוחה לא תעשה  that we have discussed, this same mechanism could not explain the principle of עשה דוחה עשה , making them two unrelated principles, rather than “sister principles” as we assumed!

It remains for us to suggest an alternative explanation for the dynamics of at least this second principle!

Hopefully we shall have a chance in the future to do precisely that.

These posts are intended to raise issues and stimulate further research and discussion on contemporary topics related to the daf. They are not intended as psak halacha.

Shabbos 132 עשה דוחה לא תעשה and מצוה הבאה בעבירה- Does the end justify the means?

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On this daf, we discuss the reason why one is permitted to perform a bris on Shabbos, despite the fact that the forbidden melacha of making a wound is an inevitable part of the removal of the foreskin.
We also discuss why it is permitted to perform a bris on someone who has a leprous lesion on the site of the bris.
Various reasons are given for the former, but the most accepted view seems to be that   of Rabbi Yochanan who learns it from the passuk וביום השמיני ימול, (on the eight’s day he shall be circumcised), the derasha being “even on shabbos.”
The later is also derived from a similar דרשה- “בשר אע”פ שיש שם בהרת ” but there is also a view that it is because the positive command of performing a bris pushes aside the negative command of cutting off a leprous lesion,  
This in turn, together with the permission to wear linen tzitzit on a woolen garment or vice versa, seems to serve as examples of  a general rule by which a positive mitzva pushes aside a negative one – עשה דוחה לא תעשה (see the  long sugya in the beginning of Yevamos for a more detailed discussion regarding the source for and parameters of this rule.)
There is, however, another commonly applied rule, which seems to state the complete opposite, and that is the rule of מצוה הבאה בעבירה (A mitzva that comes in/with/from a sin.)
The most famous example of this is found in the Mishna (Sukkah 29b) where we are told that a stolen Lulav is not fit for fulfilling the Mitzva.
Not only does one get punished for stealing the Lulav, but one also does not get the reward for taking the Lulav- not only do the ends NOT justify the means, the means invalidate the end!
Why does one simply not apply the former principle of עשה דוחה לא תעשה  and say that the positive commandment to take the Lulav pushes aside the prohibition of stealing, not only validating the ends (the mitzva of Lulav,) but also the means (stealing it.)
The most obvious distinction can also be found on our daf.
The Gemara is dealing with a case where a person wants to perform service in the Temple but is impure due to a leprous lesion.
It wants to know why the rule of עשה דוחה לא תעשה cannot be applied to allow him to remove the relevant lesion in order to fulfil the mitzva of the divine service.
  Rav Ashi answers that the rule of עשה דוחה לא תעשה only applies when one transgresses the prohibition at the SAME time as one performs the Mitzva.
The logic might be that an action needs to be defined one way or another as either something positive or something negative.
The Chidush (novelty) of this rule is that when ONE action contains both a Mitzva and an aveira, the action is defined as positive, based on the mitzva, rather than negative, based on the aveira.
However, where two separate actions are involved and the prohibition does not take place simultaneously with the mitzva but rather beforehand, like in this case where a person first removes a lesion in order to later be able to perform the service, this reasoning does not apply, and the original prohibition cannot be permitted.
It thus follows from the chiddush of מצוה הבאה בעבירה  that seeing as the original prohibition was not permitted at all, the mitzva that is fulfilled later as a result of the prohibition is also not considered a mitzva at all.
Similarly in our case, seeing as the Lulav is first stolen and only used afterwards for the mitzva, the rule of עשה דוחה לא תעשה  does not apply, and the rule of מצוה הבאה בעבירה  then comes and invalidates even the mitzva.
The problem with this approach is that it could technically be possible to perform the mitzva of lulav at the same time as he steals it.
If one grabs a Lulav from someone on Sukkot and at the same time as  he makes the קנין גזילה   (symbolic act that affects the transaction, in this case giving it the status of a stolen object,) he has intention to fulfil the mitzva of taking it, the rule of עשה דוחה לא תעשה  should surely apply?
Perhaps the answer lies in another rule we have learnt on our daf, namely the reason the Gemara itself has issues with deriving the permission to perform a bris on the site of a leprous lesion: אין עשה דוחה לא תעשה ועשה – a positive commandment can not push aside a prohibition which also involves a positive commandment.
In the case of stealing, there is not only the negative commandment against stealing, there is also the positive command to return whatever one has stolen.
So long as one is still in possession of stolen property, one has not only transgressed the prohibition of stealing, but has avoided the command to return it.
If a person steals a lulav and simultaneously takes it, he is not only transgressing the prohibition of stealing the Lulav- he is also avoiding the Mitzva of returning it.
Thus the rule of עשה דוחה לא תעשה cannot possibly apply, and the rule of מצוה הבאה בעבירה prevents one from fulfilling the Mitzva.
 
In truth, The rule of מצוה הבאה בעבירה also seems to be found in other cases where the prohibition is performed at the same time as the Mitzva.
For example, one who eats מצה של טבל (matza from untithed produce) on Pesach, one  does not fulfill the Mitzva of eating matza, even though the prohibition of eating untithed produce has been performed simultaneously with the mitzva )Pesachim 35a)
However, the Gemara brings a separate passuk to prove this, and although our argument could possibly also be applied to the case of  טבל too, seeing as there is also a positive mitzva to separate the various tithes, we will leave that till Pesachim bli neder.
All this is on the level of technical halachik pilpul.
Yet on an ethical level, the fact that we clearly do not apply the rule of עשה דוחה לא תעשה to stealing, or as far as I am aware, other מצות בין אדם לחבירו can easily be understood.
It is one thing to trade-off one mitzva with another when both are between man and Hashem.
However, if your mitzva will be at the expense of someone else, this goes against the very idea of what mitzvot are supposed to accomplish and is also a tremendous Chillul Hashem.
On such things, Hashem says “”חדשיכם ומועדיכם שנאה נפשי (my soul has hated your new-moons and your festivals- Yeshayahu 1/14/)
Going into the 9 days, this message is more relevant than ever.
These posts are intended to raise issues and stimulate further research and discussion on contemporary topics related to the daf. They are not intended as psak halacha.