Sheviis, Chapter 6, Mishnah 5. Our Mishnah establishes that we do not export oil designated for burning from Eretz Yisrael to outside the Land, and likewise we do not export produce of Sheviis whose time for removal has arrived.
What is oil designated for burning?
Oil designated for burning is oil of Terumah that became tamei, and therefore must be burned. In practice, a kohen is permitted to derive benefit from this oil while it burns - to heat the oven with it, to light a lamp with it, and the like.
The novelty of the Mishnah is that the place of burning is defined: the burning of the oil must take place specifically in Eretz Yisrael, and it may not be taken out of Eretz Yisrael to outside the Land. The same applies to produce of Sheviis that is to be destroyed once the time for removal has arrived - the removal must be carried out in Eretz Yisrael, and the produce may not be taken outside the Land.
The reason for the halachah:
The reason is that we learn this from the law of consecrated offerings: the meat of sacrifices that became disqualified must be burned in its own place, each one according to the place where it may be eaten:
Sacrifices that may be eaten anywhere in Jerusalem - their burning is done anywhere in Jerusalem.
Sacrifices that may be eaten only in the Azarah, the courtyard of the Beis HaMikdash - their burning is done in the Azarah.
This halachah, which applies to consecrated offerings, was extended also to oil of Terumah that must be burned, and likewise to produce of Sheviis that must undergo removal.
The words of Rabbi Shimon:
"Amar Rabbi Shimon" - Rabbi Shimon comments on this halachah: "shamati b'feirush shemotzi'in l'Surya" - that is, it is permitted to take oil designated for burning and produce of Sheviis out to Syria, even though Syria does not have the status of Eretz Yisrael itself. On the other hand: "v'ein motzi'in l'chutz la'aretz" - and we do not take them outside the Land.
The precise reading of the later authorities:
A number of the later authorities point out that the final halachah, "and we do not take them outside the Land," was already included in what was stated earlier. They therefore explain that the Mishnah means that even according to Rabbi Shimon, who permitted taking the produce out to Syria, one may not take it even from Syria itself to outside the Land. In other words: this stringency applies in Syria as well, and although Syria does not have the status of Eretz Yisrael in every respect, one may not take produce from there to outside the Land.
In summary: In this Mishnah we learned that oil designated for burning - oil of Terumah that became tamei and must be burned - and produce of Sheviis whose time for removal has arrived may not be taken out of Eretz Yisrael to outside the Land, and their burning and removal must be carried out in the Land. The reason for this is derived from the law of consecrated offerings, that a sacrifice which became disqualified is burned in the place where it may be eaten. Rabbi Shimon testified that it is permitted to take them out to Syria, and according to the precise reading of the later authorities, even from Syria one may not take them outside the Land.