Rabbi Yannai read this verse about him: “And to him who orders his way, I will show the salvation of God” (Psalms 50:23), for he considered his conduct and determined when it was inappropriate to challenge his master.

§ With regard to the halakhot of marking graves, the Sages taught the following baraita: The courts do not mark the area of an olive-bulk of a corpse; nor of a bone that is the size of a barleygrain-bulk; nor of any item that imparts impurity only through physical contact but does not impart ritual impurity by means of a tent to an individual or object that it overshadows, or that is overshadowed by it, or that is found together with it under the same structure. But they do mark the area of the spine of a corpse, the skull, or the bones that comprise the majority of the skeletal structure or the majority of the number of bones in the body.

And furthermore, they do not mark the area of certain ritual impurity, i.e., a place that is known to all as ritually impure, but they do mark a place of uncertain ritual impurity. And these are the places of uncertain ritual impurity: Overhanging boughs, protrusions, and a beit haperas. And they do not erect the marker directly over the site of the ritual impurity, so as not to cause a loss of ritually pure food items, as one who is carrying such food might inadvertently walk up to the site of ritual impurity and only then notice the marker, after the food has already contracted impurity. Similarly, they do not distance the marker from the actual site of ritual impurity, so as not to cause a loss of Eretz Yisrael, i.e., so as not to increase the area into which individuals refrain from entering.

The Gemara begins to analyze this baraita by asking: Is it really so that an olive-bulk of a corpse does not impart ritual impurity by means of a tent? But didn’t we learn in a mishna (Oholot 2:1): These are the items that impart ritual impurity by means of a tent, and among other items this list includes an olive-bulk of a corpse?

Rav Pappa said: Here, we are dealing with a case where the piece of flesh is exactly an olive-bulk, which, as it decays, will ultimately diminish in size to less than an olive-bulk. Accordingly, it is preferable that teruma and consecrated items be burned because of it for the time being, in a case where one inadvertently encounters this impurity because it was not marked and consequently one must burn any teruma or consecrated items that became ritually impure, and not be burned because of it forever afterward. After some time the piece of flesh will be less than an olive-bulk, yet if the area is marked, people will continue to burn teruma or consecrated items because of it, as, due to the marking, they will assume that ritual impurity was imparted by means of a tent.

The Gemara continues to explicate the baraita: And these are the places of uncertain ritual impurity: Overhanging boughs, and protrusions, and a beit haperas.

The Gemara explains: Overhanging boughs is referring to a tree that hangs over the ground next to a cemetery, and under one of its branches there might be a corpse. If there is a corpse there, the branch overhanging it creates a tent and therefore imparts ritual impurity to anyone who passes underneath it.

Protrusions is referring to protruding stones that jut out from a wall and are not flush with it, under which there might be a corpse. Once again, if the stones protrude over a corpse, they create a tent and impart ritual impurity to anyone who passes underneath.

The definition of a beit haperas is as we learned elsewhere in a mishna (Oholot 17:1): One who plows a field containing a grave, thereby raising concern that bones may have become strewn throughout the field, renders the field a beit haperas. And how much of the field does he render a beit haperas? The full length of a furrow, which is a hundred cubits.

The Gemara asks: Does a beit haperas really impart ritual impurity by means of a tent? But didn’t Rav Yehuda say that Shmuel said: If a person is carrying ritually pure items or wishes to remain ritually pure so that he may consume consecrated items, yet he must cross a beit haperas, he may blow upon the earth in the beit haperas before each step to clear away any small bones that may have become strewn across the field and proceed to walk across the area, thereby remaining ritually pure. This indicates that there is no concern about contracting ritual impurity by means of a tent in a beit haperas; otherwise, it would be prohibited to cross in this way, as it is possible that in the course of blowing one may already have contracted ritual impurity by leaning over the bones or by passing over bones that are buried beneath the surface.

Similarly, Rav Yehuda bar Ami said in the name of Ulla: A beit haperas that was trampled, i.e., a well-trodden beit haperas, is ritually pure, as passersby have certainly cleared away any bones with their feet. If a beit haperas were to impart ritual impurity by means of a tent, there should be a concern that the bones may have been trampled upon and buried in the ground. Both these sources prove that a beit haperas does not impart impurity by means of tent, posing a contradiction to the mishna.

Rav Pappa said: It is not difficult, as a distinction can be made between different types of beit haperas: Here, where the baraita states that a beit haperas must be marked because it imparts tent impurity, it is referring to a field in which a grave was lost, i.e., a field that was known with certainty to contain a grave, though its precise location can no longer be recalled. There, where it ruled that a beit haperas does not convey tent impurity, it is a case of a field where a grave was plowed and it is not at all clear whether there are bones strewn across the field. In that case ritual impurity is not imparted by means of a tent, and so it need not be marked.

The Gemara asks: But is a field where a grave was plowed called a beit haperas, such that one must be concerned about its ritual impurity? The Gemara answers: Yes, and so we learned in a mishna (Oholot 18:2–4): There are three types of beit haperas through which those who eat teruma and consecrated items are prohibited to walk: A field in which a grave was lost and its precise location is no longer known, a field in which a grave was plowed and bones may have been scattered about, and a weepers’ field.

The Gemara asks: What is meant by a weepers’ field? Rav Yehoshua bar Abba said in the name of Ulla: A field where those escorting the deceased would take leave of the deceased, handing the corpse over to those who would perform the actual interment.

And what is the reason that one must be concerned about ritual impurity in a weepers’ field? Avimi said: It is due to the possible despair by the owners of recovering bones that the Sages touched upon it. There is a concern that in transporting the deceased from far away, a loose limb may have fallen from the corpse into the field, and unseen by those transporting the deceased, it was abandoned there. Since over time many corpses passed through this weepers’ field, it is assumed that ritual impurity might be found in many places throughout the field.

The Gemara asks: And does a field in which a grave was plowed not require marking? But isn’t it taught in a baraita: If one encountered a field that was marked due to ritual impurity, and it is no longer known what the nature of the ritual impurity was, if there are trees in the field, it is known that a grave was plowed in it, as it is permitted for one to plant trees in such a field. If there are no trees in the field, it is known that a grave was lost in it, as it is prohibited for one to plant trees in such a field. If a field is suitable for planting trees and yet there are none, clearly it is because a grave was lost in it.

Rabbi Yehuda says: We do not rely on these signs unless there is an Elder or a rabbinic scholar who can testify about the subject, as not all are experts in this matter, and perhaps the field was not plowed at all. In any case, this baraita teaches that a field in which a grave was plowed is also marked.

The Gemara answers: Rav Pappa said: When that baraita concerning a marked field is taught, it is taught with regard to a field where a grave was certainly lost and they immediately marked it. However, if there are trees in the field, it is known that a grave was later plowed in it, i.e., it was forgotten that a grave had been lost in the field and so it was inappropriately plowed and prepared for planting. But if there are no trees in the field, we know that a grave was lost in it and it was not later plowed.

The Gemara raises a question about this ruling: But let us be concerned that perhaps the trees were located inside the field and the grave was located outside of it, and the actual site of the grave was never plowed but simply lost? How then can one rely on the presence of trees to indicate that the grave had been plowed in the field?

The Gemara answers: It is as Ulla said elsewhere. This is a case where the trees are standing along the field’s boundaries, next to a public domain, as the grave is certainly not outside the trees in the public domain, since people do not bury a corpse in the public thoroughfare. Rather, the grave must be between the trees, and was therefore plowed. Here too, then, this is a case where the trees are standing along the borders.