Demai, Chapter Six, Mishnah Four
The first half of this mishnah is the mirror image of the previous mishnah – here an Israelite rents a field from a priest or terumah.
The second half of the mishnah deals with a person who lives outside of Jerusalem who rents a field from a Jerusalemite. The question in this section deals with second tithe, which has to be brought to Jerusalem and eaten there.
1) If an Israelite rented a field from a priest or from a Levite [for a share in the produce] the tithes belong to the owners [of the field].
2) Rabbi Ishmael says: if a city dweller [from outside of Jerusalem] rented a field from a Jerusalemite, the second tithe belongs to the inhabitant of Jerusalem.
a) But the sages say: the city dweller may go up and eat the second tithe in Jerusalem.
Section one: When the priest or Levite rented out the field to the Israelite, we can assume that he understood that he (the owner) was going to keep the terumah and tithes solely for himself. Therefore, when they go to split the produce, the owner first takes the terumah (if he is a priest) or tithes (if he is a Levite) and then the owner and the renter split the rest of the produce according to the plan.
Section two: Second tithes are brought to Jerusalem and eaten there. In the scenario in this section, a person who lives in Jerusalem rents a field to someone who lives outside of Jerusalem. According to Rabbi Ishmael, we assume that the Jerusalemite rented the field out with the understanding that he himself would receive the second tithe. Therefore, the one renting the field has to first give the entire second tithe to the owner and then they split the produce according to the agreement.
The sages disagree, noting that second tithe is not generally given to the residents of Jerusalem; it is consumed there by its owners. Therefore, second tithe is treated here like all of the rest of the produce. The renter takes his share of the second tithe and then he can bring it to Jerusalem and eat it there.