In his Commentary to the Mishnah (Ohalot 3:7), the Rambam explains that the term “square” is added to emphasize that both the width and the length must be at least a handbreadth. If the covering is only half a handbreadth wide, it is not considered as an ohel even if it is several handbreadths long.
A Talmudic measure equal to 8 cm according to Shiurei Torah and 9.6 cm according to Chazon Ish.
The Ra’avad emphasizes that unless the covering is a handbreadth above the impurity, the impurity is considered as retzutzah, “flush.” The Rambam makes this point later in the halachah.
An overhang or shelter that causes everything under it to contract ritual impurity and intervenes between ritual impurity and everything above it, as the Rambam proceeds to explain.
Our translation is taken from the Rambam’s Commentary to the Mishnah (Tamid2:1). The Rambam is giving examples of keilim that might be placed under such a small overhang.
Even though they are under the overhang. Since it does not meet the minimum requirements the laws of ohel do not apply.
See Chapter 7, Halachah 4.
E. g., keilim of stone or earth (Chapter 6, Halachah 2).
For the board served as a tent over the keilim and the impurity.
Thus the board serves as a tent to convey ritual impurity, but not to intervene in the face of it [the Rambam’s Commentary to the Mishnah (Ohalot 6:1)].
When supported by something other than a human or a utensil.
The Ra’avad emphasizes that this also applies to oversized wooden keilim (refer to Chapter 6, Halachah 2). The Kessef Mishneh states that, as evident from Chapter 13, Halachah 3, the Rambam would also accept this point and does not mention wooden keilim here for stylistic purposes alone.
I.e., that contain 40 se'ah. See Chapter 6, Halachah 2.
I.e., an oven that had not been used yet.
I.e., the board intervenes in face of the impurity.
Were it to be considered as an implement, the keilim would be impure, as stated in Halachah 1.
For the oven is considered like other keilim.
And thus considered like other keilim.
I.e., the ovens themselves create a separation, preventing the entire area from being considered as one large tent. It appears that, as in the following clause, the board is protruding beyond the ovens only at the sides, and not at the ends.
The Ra’avad objects to the Rambam’s ruling, maintaining that it is not a correct interpretation of the mishnah (Ohalot 12:1). For the mishnah appears to be speaking about a situation where the board sticks out from the ovens on all four sides. Hence, the entire area is considered as one ohel. The Kessef Mishneh admits that the simple meaning of the mishnah would appear to follow the Ra’avad’s interpretation.
Here also, the Rambam’s point is that since the board protrudes only on the sides and not on the ends, the oven sets them apart. Hence the areas are considered as two tents and not one.
Our translation is based on early printings and authentic manuscripts of the Mishneh Torah and is supported by the Rambam’s Commentary to the Mishnah (Ohalot 16:1). The standard published text has a slightly different version.
In his Commentary to the Mishnah (lac. cit.), the Rambam cites Keilim 17:8 which states that the ordinary circumference of a plow was a handbreadth.
As the Rambam states at the conclusion of Halachah 8, he is speaking in approximations. A handbreadth is four fingerbreadths. Following the mathematic formula that the circumference is equal to the diameter times pi, one and a third times pi is slightly more than four.
He is considered as one who touched a utensil that was held over a corpse [the Rambam's Commentary to the Mishnah (loc. cit.)]. Accordingly, he contracts impurity that lasts seven days and must be purified by having the ashes of the Red Heifer sprinkled on him. This stringency was imposed lest one think the impurity of ohel is of a lesser status than other impurities. This is one of the stringencies imposed on the day when the students of the School of Shammai outnumbered the students of the School of Hillel (Shabbat 1:4).
By a handbreadth, as stated in Halachah 1.
One who walks upon a grave is impure. See Chapter 2, Halachah 15.
The Rambam. derives this halachah from the account of Rabbi Elazar ben Tzadok in Berachot 19a which relates that he (who was a priest and thus forbidden to contact impurity) and others would hurry over the coffins to see the kings of Israel. The Rambam postulates that they were coffins made of wood and that the Sages relaxed the decree mentioned here out of respect for the monarchy. The Ra’avad differs and maintains that the passage is speaking about stone coffins that were used in Eretz Yisrael at that time.
I.e., they are not considered as independent entities, but as part of the entire ohel. Hence, since a portion of it is large enough to convey ritual impurity, its entire span - even those portions that are not wide enough - are considered as part of the ohel.
For a length of a handbreadth.
Chapter 7, Halachah 4. Thus only the keilim or persons who are in the space directly above or below the source of impurity become impure.
Here also, the Rambam is speaking in approximations. Since circumference is pi times the diameter, for a board to be a handbreadth in width it would have to be slightly more than three handbreadths in circumference.
Thus, each side of the board would be a handbreadth,
If there is a cover over it, everything is impure because it is under the larger cover.
I.e., when dividing the circumference of 4.5 by pi, the diameter will be slightly less than 1.5.
Since the barrel is hollow, we consider its upper portion as constituting a covering, even if it is enclosed on the bottom. There will be a portion of the barrel that is more than a handbreadth by a handbreadth in area that is one handbreadth above the ground.
Because here too there will a portion more than a handbreadth by a handbreadth of the upper portion of the barrel above the ground.
Unlike the barrel, the pillar is not hollow. Hence, for it to be considered as an ohel, there must be a portion of its circumference a handbreadth by a handbreadth that is above the ground (Kessef Mishneh).
If it is that large, it conveys impurity to all keilim under it, even those that are under portions that are less than a handbreadth above the ground.
Actually, slightly less than one.
More specifically, a handbreadth times the square root of two which is 1.41.
If the pillar is 24 handbreadths in circumference, an imaginary square, 8 handbreadths by 8 handbreadths, can be circumscribed around it. [This is an approximation. Actually, the diameter will be slightly less 8.] Thus the length of the diagonal will be approximately 11 handbreadths. Since the radius of the pillar is slightly less than 8 handbreadths, the midpoint of the portion of the pillar above the ground will be approximately 1.6 handbreadths from the comer of the imaginary square and thus that point will be more than a handbreadth above the ground. Moreover, there will be more than a handbreadth of space from that point to the end of the imaginary square. Thus there will be more than a square handbreadth of space on the pillar that is a cubit above the ground,
Although lacking in the standard published versions of the Mishneh Torah, these words and the diagram were included in the authorized manuscripts.
