By Rav Shelomo Levi
The Mishna in Sukka (21b) records a dispute about one who supports his sukka with the legs of a bed. The anonymous first Tanna of the Mishna says that such a sukka is fit, whereas Rabbi Yehuda says that if the sukka cannot stand on its own, it is unfit. In the Gemara, the Amoraim disagree as to Rabbi Yehuda's rationale:
Rabbi Zera and Rabbi Abba bar Memel disagree. One says: Because it has no permanence. And the other says: Because he supports [the sukka] with something that contracts ritual impurity.
This second understanding of Rabbi Yehuda's position is the source for the prohibition to support sekhakh with something that contracts ritual impurity. Before we consider questions of practical Halakha, let us try to understand the reason for this prohibition.
The Ra'avad, the Ramban, the Ritva and the Ran all explain that we are dealing here with a rabbinic decree, lest someone come to use unfit sekhakh. (Sekakh cannot be made out of something that can contract impurity.) According to them, there is no problem here according to Torah law, for the laws of sekhakh apply exclusively to the sekhakh itself, and not to the walls of a sukka, everything being fit to serve as walls of a sukka. The Sages, however, decreed that a person should not support his sekhakh with something that contracts ritual impurity, lest he come to use that same material for the sekhakh itself.
Rashi, ad loc., seems to disagree. For Rashi explains:
Even though we only learned this disqualification regarding sekhakh, since [the ma'amid] supports the sekhakh, it is as if he used that which contracts ritual impurity for sekhakh.
Rashi seems to imply that we are not dealing here with a decree lest he come to use the disqualified material for sekhakh, but rather "it is as if he used that which contracts ritual impurity for sekhakh." An obvious objection may be raised: Surely, in the end, the support is not part of the sekhakh, so why should we view the situation as if he used the disqualified material for sekhakh?
The Bach (sec. 629), in explanation of Rashi, writes: "[This follows from that which] we maintain in general, namely, that all follows the ma'amid (that which gives food its form and substance)." This argument, however, requires explanation. Do we maintain in general that all follows the ma'amid? The law of ma'amid usually relates to mixtures of forbidden food, where one food becomes commingled with another and gives it form or essence. For example, if rennet from the stomach lining of a non-kosher animal is mixed with milk, it causes it to stand, i.e., to curdle and turn into cheese. In other examples as well, e.g., non-kosher yeast, we are talking about a forbidden food that becomes mixed up with a permitted food. The law that states that a ma'amid is not nullified does not create any new prohibition, but rather prevents bittul – annulment of the non-kosher food. In general, a forbidden food becomes annulled when mixed with a majority or sixty parts of permitted food. Something that is a ma'amid, however, does not become annulled. The cheese is forbidden, because it contains the non-kosher rennet that was not annulled, and since it cannot be separated out, the entire cheese is forbidden.
In light of all this, it is very difficult to compare this to the ma'amid (support) of sekhakh. Surely the support is not intermingled with the sekhakh; it is underneath the sekhakh. In order to permit the sukka, there is no need to annul the support, because it is not at all used as sekhakh. How, then, can one say that it is as if he used the ma'amid as sekhakh? Surely in the ordinary case of ma'amid, we are talking about a ma'amid that is found inside the food that becomes forbidden.
We are forced, then, to the conclusion that the Bach understood the law of ma'amid differently. We are not talking about mere non-annulment. Rather, the law is that food that is given form by some non-kosher ingredient becomes entirely forbidden, because that which gives it form is forbidden.
This may be compared to the idea of davar ha-gorem, mentioned in Pesachim. The Gemara there talks about bread that was baked in an oven fired with the wood of an ashera (a tree worshipped as part of idolatrous rites). Entirely burned and consumed, the wood no longer exists, but it caused the dough to turn into bread. The novelty of the prohibition applying to this bread is that even though the original object of prohibition no longer exists – for the forbidden wood is now ashes – since the dough changed form on account of the prohibited object, this change is regarded as sort of a perpetuation of the prohibited object in the bread itself. The baking of the bread relates to the forbidden wood, even though that baking is not a separate object, but a state in which that object exists. Apparently, however, a prohibition can apply even to a state. In other words, an object that has been affected by that which is forbidden becomes prohibited even when the original object of prohibition no longer exists, and that which does exist is the new state created by the forbidden object.
The Bach apparently understood the principle of ma'amid in this manner. The cheese is not forbidden because of the rennet that was not nullified, but because it curdled on account of that which is prohibited. The prohibition of the rennet applies to the change from milk to cheese, even without relating to the rennet itself as a forbidden food within the cheese.
Support for the Bach may be adduced from the words of Rabbenu David to Pesachim 26b. Rabbenu David emphasizes there regarding ashera wood:
Even though… the wood leaves in the bread neither taste nor substance… nevertheless the improvement and new state of the bread is what is forbidden.
In the continuation of his words, Rabbenu David himself compares this law to the law governing yeast that leavens bread. He writes:
Even though something itself that is forbidden fell into it, it is nullified in it… and it is forbidden only because of the leavening, and the leavening is neither taste nor substance, but rather a state that was added to the dough.
The Bach seems to maintain that the same law applies to a sukka. There is no external change in the wood used as sekhakh, as there is in the cheese or in the bread, but its status changes. Previously it had merely been wood, but now it is sekhakh that turns the hut into a sukka. A change similar to the baking of bread exists also in the wood that serves as sekhakh. Therefore, if this change is effected by that which is disqualified, then in this wood there now lies also the qualities of the ma'amid. It is as if there is in the sekhakh something that contracts ritual impurity and disqualifies all the sekhakh.
Thus far, we have attempted to clarify the position of Rashi according to the Bach. As was stated above, however, the Rashba and the Ran understood that we are dealing here with a rabbinic decree. They apparently maintain that it cannot be argued here that the wood undergoes a change, as do the cheese and the bread, and therefore in the sekhakh itself there is nothing there now to disqualify it by Torah law.
As for normative law, the Rishonim disagree on two points: 1) Does the law follow Rabbi Yehuda or the Sages? 2) If the law is in accordance with Rabbi Yehuda, what is the concern?
The Rif cites the words of Abaye in the Gemara, ad loc.: "This only applies where he supported [the sukka with the legs of a bed], but if he spread the sekhakh on the bed – it is fit." Abaye's statement is only necessary according to Rabbi Yehuda, for according to the Sages, even if he supported the sukka with the legs of the bed, the sukka is fit. Thus, several Rishonim infer from this that the Rif ruled in accordance with Rabbi Yehuda. He ruled in this manner, explains the Rashba, because the talmudic discussion revolves around the position of Rabbi Yehuda, implying that the Halakha follows his view.
In contrast, the Rambam states explicitly in his commentary to the Mishna that the law is not in accordance with Rabbi Yehuda, and therefore he does not bring the law in his code. This is also the position of the Ba'al ha-Ma'or (ad loc.), the Ravya (II, no. 631) and other Rishonim.
Rashi does not relate directly to the question of final Halakha, but his position on the matter may be inferred from a careful reading of his words. He explains that according to the position that Rabbi Yehuda disqualifies a sukka that is supported by the legs of a bed because it is not considered a permanent structure, Rabbi Yehuda follows his own position stated elsewhere that a sukka requires permanence (as opposed to the Sages, who maintain that a sukka must be a temporary structure). Inasmuch as it is clear that the law must be the same in both places, perforce it follows that if we do not rule in accordance with Rabbi Yehuda regarding the need for a permanent structure, we should also not rule in accordance with him regarding a sukka supported by the legs of a bed. There is, however, no proof according to the position that Rabbi Yehuda disqualifies the sukka because of ma'amid. According to this, however, the argument put forward by the Ramban and other Rishonim that the law must be in accordance with Rabbi Yehuda because the Amoraim discuss his position, falls to the wayside. For there is at least one Amora who discussed Rabbi Yehuda's position, even though the law is not in accordance with it. Had the Gemara thought that according to the second position in the Gemara the law is in accordance with Rabbi Yehuda, perhaps it should have mentioned this as a practical ramification between the two understandings.
Thus, it seems clear that Rashi maintains that the law here is not in accordance with Rabbi Yehuda. The other Rishonim do indeed disagree with Rashi in their understanding of Rabbi Yehuda, arguing that all agree that there is no connection between what Rabbi Yehuda says here and what he says at the beginning of the tractate regarding the need for a permanent structure.
The Ramban and others who ruled in accordance with Rabbi Yehuda also took into consideration the position that Rabbi Yehuda disqualifies the sukka because of the problem of ma'amid. Thus, they ruled that it is forbidden to support a sukka with that which is unfit to be used as sekhakh. The Rosh records another position. The Rosh concludes that indeed one must be concerned about the view of Rabbi Yehuda, but not because of the problem of ma'amid, but because of the need for permanence. According to him – following the Yerushalmi - permanence here means that there be ten tefachim of usable space in the sukka. Therefore the Rosh adds: How can the Sages possibly disagree with this? He concludes that perhaps in fact the first Tanna of the Mishna agrees with Rabbi Yehuda on this point.
The Bet Yosef cites the various opinions, and in the Shulchan
Arukh (end of sec. 630), he rules in accordance with the Rosh, who maintains
that there is no problem whatsoever of ma'amid. He, therefore, permits a
person to spread out sekhakh over the legs of a bed, provided that there
are ten tefachim between the bed and the sekhakh. The Rema voices
no disagreement with the Shulchan Arukh. Elsewhere, however, the
Shulchan Arukh writes (629:3): "A doubt arises as to whether it is
permissible to lay a ladder across the roof for sekhakh." The Taz
in nos. 9 and 10 understands that the doubt relates to the use of a ladder
as sekhakh¸ and is unconnected to the problem of ma'amid, about
which the Shulchan Arukh and the Rema issued a lenient ruling in sec.
The words of the Bet Yosef seem to support the Taz, for he brings the responsum of the Ramban which he also cites in the Shulchan Arukh, according to which the words, "A doubt arises," do not relate to a case of ma'amid. For he says this in relation to the words of the Terumat ha-Deshen – who is lenient on the matter of a ladder – who explicitly deals with the law regarding a ladder itself, and not with ma'amid, regarding which he accepts the position of the Rosh cited above.
As for the Halakha, many Acharonim agree with the Magen Avraham that at least lekhatchila one should be stringent and refrain from supporting the sekhakh with something that contracts ritual impurity, and this indeed is the customary practice. However, in a situation of great need, and in the absence of viable alternatives, one can rely on the simple reading of the Shulchan Arukh and the Rema, according to which there are no restrictions whatsoever on that which supports the sekhakh.
Regarding materials that are disqualified for use as sekhakh only by rabbinic decree, like broken pieces of utensils, many Acharonim are inclined to say that one may be lenient about them even lekhatchila. This is because even according to the Ran – whose position has been accepted as Halakha – the prohibition regarding ma'amid is only by rabbinic decree, and therefore there is no second decree regarding something that is prohibited only by rabbinic decree. This position is stated explicitly by the Ritva.
One issue that remains in dispute is the question of ma'amid dema'amid, a second-degree ma'amid - that is, something that supports the support of the sekhakh. The Shulchan Arukh in sec. 629 writes that the poles that support the sekhakh may be reinforced with nails. The Magen Avraham explains that while the nails are unfit to be used as sekhakh, here they serve merely as a second-degree ma'amid, reinforcing the poles that support the sekhakh, and therefor they are permitted even lekhatchila. The Chazon Ish in sec. 143 disagrees with the Magen Avraham, arguing that material that is unfit to serve as sekhakh may not be used even as a second-degree ma'amid. The Chazon Ish puts forward two arguments: 1) The wording of the Ramban and the Ran indicates that they only permit the support of sekhakh on poles that are standing on the ground, and that they do not issue a general allowance regarding a second-degree ma'amid. 2) The material that is fit to be used as sekhakh which is now supporting the sekhakh is itself disqualified because it is supported by something that is disqualified for use as sekhakh. In other words, in every case of an unfit second-degree ma'amid, the ma'amid itself is regarded as disqualified, and so the sekhakh is supported by an unfit ma'amid.
The Chazon Ish's argument must be examined both according to the reasoning of the Ran and according to the reasoning of the Bach.
According to the Ran, who believes that we are dealing with a rabbinic decree lest a person come to use the unfit material for the sekhakh itself, it is certainly possible to argue that the Sages only issued their decree about a first-degree ma'amid, because of its proximity to the sekhakh, but not about a second-degree ma'amid. For the first-degree ma'amid does not turn into unfit material, just because it is supported by unfit material. According to the Bach as well, there is room for leniency, for even if we say that it is as if the ma'amid exists in that which it supports, it is possible to distinguish and say that this applies only when the ma'amid causes the sekhakh to be fit sekhakh and remain standing in its place. When, however, the nails cause the poles to become supports, that type of impact is not regarded as a significant change in status so that the support should become forbidden as a result.
1. It is customary not to support the sekhakh itself with anything that is unfit to be used as sekhakh, unless there is great need and no other alternative presents itself.
2. If the support is unfit to be used as sekhakh only because of a rabbinic decree (e.g., flat wooden utensils, broken pieces of utensils), some Acharonim permit its use even lekhatchila.
3. All agree that one is permitted to support the sekhakh with walls that are attached to the ground, because there is no concern that a person will come to use them for sekhakh.
4. Regarding a second-degree ma'amid, the Magen Avraham and many Acharonim rule leniently, whereas the Chazon Ish is stringent.