Rambam - 1 Chapter a Day

In Chapter 2, Halachah 16, the Rambam mentioned that the Sages deemed a beit hapras impure. Here he explains the situation in detail. In his Commentary to the Mishnah (Ohalot 17:1), the Rambam explains that the name has the implication “spread out,” i.e., a place where portions of bones could have been spread out.

Thus, in this and in the subsequent instances, it is impossible that the bones of the corpse were disturbed.

Our Sages (Ohalot, loc. cit.,) estimated that it was possible that the bones of the corpse could be carried this far by a plow.

Not just the furrow plowed.

I.e., the 100 cubit by 100 cubit area.

As explained in Eruvin 23b, the area in which a se’ah can be sown is 50 cubits by 50 cubits.

Chapter 2, Halachah 16.

In either of these instances, any bone the plow was carrying would have fallen off.

After waiting, without shaking out the plow.

Even though he did not shake out the plow.

Because it is not common to bury animals, nor is it common to leave humans unburied.

From the Rambam’s wording, it appears that this leniency applies even if one plowed the entire field. Rabbenu Shimshon maintains that in such a situation, a beit hapras is created.

I.e., it was known that a grave had existed in that field, but its location was not known.

The grave that was discovered was not plowed. However, one might think that there was another grave in the field that had been plowed [the Rambam's Commentary to the Mishnah (Ohalot 17:3)].

This principle is stated in several sources, e.g., Hilchot Avodat Kochavim 8:1, Hilchot Shechitah 2:21, Hilchot Issurei Mizbeiach 4:5. In those sources, however, the matter is dependent on the person’s intent and we can understand why a person’s thought cannot cause property belonging to a colleague to become forbidden. In this instance, however, a deed is involved and, in such a situation, as is in fact, mentioned in Hilchot Issurei Mizbeiach, loc. cit., the deed should have an effect, even with regard to the property belonging to another individual. From the Rambam’s Commentary to the Mishnah (loc. cit.), it would appear that since this is merely a Rabbinic stringency, and we are not certain that a prohibition is in fact involved, it need not be extended beyond the circumstances in which it was imposed. Hence, there is room for leniency when the field belongs to someone else.

Even though all these individuals have a certain measure of authority over the field, since it does not belong to them, they cannot create a beit hapras there.

The field extended 100 cubits from the grave. The person plowing owned the first 50 cubits and his colleague owned the second 50. He continued plowing into his colleague’s portion of the field.

For, as stated in the first clause, this portion of the field does not belong to him.

In his Commentary to the Mishnah (loc. cit.), the Rambam states that this concept is motivated by the same rationale stated in the previous two halachot: Since a beit hapras is a Rabbinic decree, its stringency should not be extended beyond the initial circumstances for which it was instituted.

Because of the earth of the upper field.

And thus it was obvious that earth from the upper field had been deposited in the lower one.

See Hilchot Tum’at Ochalin 11:5 for a description of the precautions necessary when harvesting the fruit growing in such an orchard.

The Ra’avad questions why the Rambam adds this point. Seemingly, since the fruit from these trees and bushes is harvested by picking them from the trees, far above the ground, the reaper would have no contact with the impurity. The Kessef Mishneh states that this rationale does not negate the Rambam’s statement.

Instead of being buried deep in the ground.

I.e., the only crops that are permitted are those which, like grain, are harvested by cutting off the stalks that protrude above the ground. For, in this way, any pieces of bone that are lying on or near the surface will not be gathered with them. In contrast, when vegetables or the like are uprooted, it is possible that the remainder of bones from the corpse will be uprooted together with the produce [the Rambam's Commentary to the Mishnah (Ohalot 18:2)].
As evident from a comparison to Chapter 8, Halachah 3, the laws governing such a field are directly opposite to those governing a field in which a grave was lost.

So that the impurity is not spread to another place.

A kor is 30 se’ah. Thus we are speaking about an extremely large field. Nevertheless, if many graves were plowed, the entire field could be governed by the laws of a beit hapras.

The Ra’avad protests the Rambam’s wording, maintaining that the Rarnbam was using an incorrect version of the Tosefta (Ohalot 17:4). As the Kessef Mishneh notes, the standard text of the Tosefta follows the Ra’avad’s ruling.
The Ra’avad also maintains that this Tosefta is speaking about a situation where a grave has been lost, not one in which a grave has been plowed over. Rav Yosef Corcus (as quoted by the Kessef Mishneh) disputes that thesis.

Because the plow would get stuck in the mud.

Since it is not plowed, we do not fear that the bones will be strewn here.

One that has been checked and no remnants of a corpse were discovered.

I.e., whether a grave was lost in it or a grave was plowed in it.

The Ra’avad states that this is speaking about an instance when the trees in a field were cut down, because it is forbidden for them to grow there. The Kessef Mishneh questions his rationale for choosing such an interpretation.

The clauses above are stated word for word in Chapter 8, Halachah 10. They are restated here for the points mentioned in the concluding clauses.

For the rider did not touch or move a bone. The rationale is that even if the person or the animal carrying the rider moved a bone, he or it did so on its own power. See Chapter 1, Halachah 7.

In this instance, we fear that there was a bone under the stone and it was moved when the person walked upon it.

For our Sages made the decree universal, so it would not be open to argument on every occasion.

For it is possible that the person or the animal moved a bone and did so, because of the weight of the rider. Thus it is considered as if the rider moved it himself.

So that the pieces of bone will be caught. The Rambam also mentions sifting the earth of a beit hapras in Hilchot Korban Pesach 6:8 and Hilchot Eruvin 6:17.

For a plow will not stir earth more than three handbreadths below the surface. Hence even if there is a piece of bone there, it will not surface again.

For he has not removed all the earth that could be stirred by a plow or covered it sufficiently with new earth. It is possible that there was a piece of bone buried two handbreadth below the surface which will still be two handbreadths beneath the surface after this action was taken.

Our translation is based on the Rambam’s Commentary to the Mishnah (Ohalot 18:5) which refers to Isaiah 5:2 and explains that the term refers to clearing a surface, smoothing it out and flattening it.

Since he is fundamentally interested in preparing his property, we are not confident that he will have checked it thoroughly for bones.

In his Commentary to the Mishnah (op. cit.), the Rambam speaks of stones large enough that they could not be moved by a person by hand even if he desired to do so.