1) "ARSA D'GADA" -- THE "GOOD LUCK BED"
QUESTION: The Mishnah teaches that one who makes a Neder to prohibit himself from a "bed" is permitted to use a "Dargash." Ula explains that a Dargash is an "Arsa d'Gada" -- a special bed designated exclusively for bringing good fortune into the home, upon which no one sits or sleeps, as the MEFARESH here and RASHI in Moed Katan (27a, DH Arsa d'Gada) explain. RASHI in Sanhedrin (20a) adds that it brings good fortune through "Nichush," superstition.
Why is one permitted to set up a bed in one's home for the purpose of Nichush? The Torah explicitly prohibits Nichush (Vayikra 19:26)! Moreover, when the RAN here explains the meaning of the word "Gada" ("Gad," or "Mazal"), he cites the Gemara in Shabbos (67b) which says that a person who attempts to improve his luck by saying, "Let my Mazal ('Gad') become fortuitous," transgresses the prohibition against Nichush. Rebbi Yehudah there adds that "Gad" refers to a type of idolatry, as he proves from a verse in Yeshayah (65:11). (CHIDUSHEI HA'RAN, Sanhedrin 20a)
ANSWERS:
(a) The ROSH here explains that the Sar of Ashirus, the Divinely-appointed spiritual being in charge of wealth and success, is named "Nakid," or "refined" (Pesachim 111b, Chulin 105b). A person attracts that Sar to his home by maintaining a clean and neat home. For this reason, many people had the custom to beckon the Sar of Ashirus to visit them by keeping one bed in the home always neatly spread.
The EINAYIM LA'MISHPAT explains that the Rosh echoes the words of the SEFER CHASIDIM (#458): an act which works through supernatural means (Mazal, or Ru'ach ha'Tum'ah) is permitted if it is widely known that such an act brings about a certain result. Since that act has been tried and tested and found to be effective, relying on that act to obtain a certain result is not considered Nichush. This explains why the Chachamim caution against eating food left under a bed because of the Ru'ach ha'Tum'ah that resides there. Similarly, it is well-known that a home with a bed kept neatly spread enjoys success, and, therefore, it is not considered Nichush. (See Shabbos 67a, where the Gemara says that any act known to heal is not called Nichush; see also Insights to Shabbos 67:2:c.)
It is possible that this is the intention of Rashi here as well. The purpose of the Arsa d'Gada bed is for a type of Nichush which is permitted (Rashi in Sanhedrin calls it "Nichush" only because it works through supernatural ways).
(b) The SHITAH MEKUBETZES writes that the Arsa d'Gada bed is not actually spread for good luck, but rather it is intended to welcome the heavenly emissary that Hash-m sends to bring wealth to a home. By honoring the emissary, one honors the One who sent him. Hence, the bed is unrelated to Nichush.
The Shitah Mekubetzes compares the Arsa d'Gada bed to the Kisei Shel Eliyahu set up at every Bris Milah to honor Eliyahu ha'Navi, the visiting emissary of Hash-m. (According to this explanation, it appears that it was only a Jewish practice to spread such an "emissary bed." It demonstrated a family's trust and confidence in Hash-m that He will send His Divine emissary to bring bountiful blessing to the home.)
(c) The RAN in Sanhedrin (20a) answers that the Arsa d'Gada was not made for Mazal at all. Rather, it was a form of expression of gratitude to Hash-m. By spreading a bed which is not even used, one shows that he recognizes that Hash-m has blessed him with more than he needs. The word "Gada" ("Mazal") in this context is a borrowed term. (Through thanking Hash-m for what He has given in the past, one merits to have more blessing in the home, and thus such a bed indeed brings wealth.) (See also Insights to Moed Katan 27:1).
2) SEATING THE KING UPON A "DARGASH"
QUESTION: The Mishnah teaches that one who makes a Neder to prohibit himself from a "bed" is permitted to use a "Dargash." Ula explains that a Dargash is an "Arsa d'Gada" -- a special bed designated exclusively for bringing good fortune into the home, upon which no one sits or sleeps (see previous Insight). The Gemara challenges Ula's explanation from the Mishnah in Sanhedrin (20a) which states that when a Jewish king is in mourning and the Se'udas Havra'ah is brought to him, all of the people sit on the ground and the king sits on the "Dargash." The Gemara asks that if a Dargash is an "Arsa d'Gada," why is the king allowed to sit on it when he is an Avel, if he does not sit on it during the rest of the year? Why is he given more honor during Aveilus? The Gemara answers that during Aveilus, the Avel indeed is given things of honor which he is not accustomed to receiving.
Why, though, is it necessary for the king to sit on a Dargash? It seems clear that the objective behind the Mishnah's ruling there is that the king retain his honor even while he is an Avel. To this end, everyone else sits lower down on the ground while the king sits in an elevated position. Why, though, is he seated upon a Dargash? If he is allowed to sit higher up despite his Aveilus, he should sit on a couch ("Mitah") in the manner in which he sits during the rest of the year! Why is he allowed to sit on a Dargash, which affords him more honor than he receives during the year, when it is not necessary?
ANSWER: The Gemara cites a Beraisa which teaches that an Avel must overturn all the beds in the house, even those upon which he does not sit. This statement includes two distinct Halachos: an Avel should not sit on a bed, and the beds in the house must be overturned even if the Avel does not sit on them. (It is because of this second Halachah that the Beraisa later needs to teach that a Mitah on which utensils are placed does not have to be overturned; see ROSH, Moed Katan 3:78.) The Chachamim were lenient and allowed a king to sit on an elevated place because of his honor, and therefore in the case of a king they eased the restriction which prohibits an Avel from sitting on a bed during Aveilus. However, they did not want to remove both Halachos -- the prohibition against sitting on a bed and the requirement to turn over the beds in the house -- if not necessary. Therefore, they sought something which does not need to be overturned upon which the king could sit, and thus they enacted that the king sit on a Dargash (which does not need to be overturned), rather than on a bed (which needs to be overturned).
(The Mishnah in Moed Katan follows the view of the Tana Kama in the Beraisa cited on 56b who argues with Raban Shimon ben Gamliel and maintains that it is not necessary to undo the straps of the Dargash, effectively turning it over. See RAN to 56b, DH b'Shuka.)
However, the RAMBAM (Hilchos Avel 5:18) writes that it is not enough to overturn the beds in the house; the Avel must also sit upon the overturned beds (and not on a chair, or even on the floor). The ruling of the Rambam implies that the Mitzvah to turn over the beds is not fulfilled unless the Avel actually sits on an overturned bed. Although the other Rishonim (see HAGAHOS HA'HASHLAMAH and TUR) disagree with the Rambam in this matter as mentioned above, the Rambam does associate turning over the beds to sitting on an overturned bed. According to the Rambam, if the Chachamim suspended the requirement to sit on an overturned bed in the case of a king who is an Avel, there should be no necessity at all for a king to overturn the beds! Since the Rambam seems to rule that the purpose of turning over the beds is to enable the Avel to sit on an overturned bed, the king might as well sit on an ordinary bed which is not overturned!
The answer is that the Rambam agrees that the requirement to sit on an overturned bed and the requirement to turn over the beds are two distinct Halachos. This is clear from the fact that the Rambam writes (Hilchos Avel 5:18) that an Avel is required to sleep on an overturned bed, which implies that he may sit on the ground and does not need to sit on the overturned bed. This is more evident from the Rambam's ruling earlier (Hilchos Avel 4:9) where he writes that on the first day of Aveilus, the Avel may not eat from his own food, and he is obligated to sit on an overturned bed. This implies that during the remaining days of Aveilus, the Avel is not required to sit on an overturned bed (but he may sit on a mat or on the floor).
The RADVAZ and others explain that the Rambam understands that there are three different Halachos which describe how an Avel sits during Aveilus. The first Halachah is that all of the beds must be overturned. The second Halachah states that the Avel is obligated to sleep on an overturned bed during the entire period of his Aveilus, although he is not required to sit there during the last six days of the Aveilus. The third Halachah states that on the first day (or during the time when others must feed him and he may not eat of his own food), the Avel must also sit on an overturned bed.
Accordingly, the Rambam may understand that the Chachamim removed the necessity for the king to sit on an overturned bed (in order to maintain his honor), but they did not suspend the other two Halachos. Therefore, the king still must overturn all of the beds in his home (and he must sleep on an overturned bed). At the Se'udas Havra'ah, the king must be seated upon something other than a bed, and that is why he is seated upon a Dargash. (M. Kornfeld)