Gittin 8B

כקונה בפרוארי ירושלים. חייבת במעשר ובשביעית כארץ ישראל ⁠– קסבר כיבוש יחיד שמיה כיבוש.

is like one who purchases a field in the outskirts [parvarei] of Jerusalem. The Talmud clarifies: The tanna who says Syria is obligated in tithe and the mitzvot of the Sabbatical Year like Eretz Yisrael holds that the conquest of an individual is called a conquest. Once Syria was conquered by King David, who is considered an individual in this regard, the sanctity of Eretz Yisrael applied to it and its residents became obligated in the mitzvot of Eretz Yisrael.

והרוצה ליכנס לה בטהרה נכנס ⁠– והאמרת עפרה טמא? בשידה, תיבה ומגדל.

The baraita teaches: And one who wishes to enter it and remain in a state of ritual purity may so enter. The Talmud asks: But didn’t you say that its soil is ritually impure? How then is it possible for one to enter it in a state of ritual purity? The Talmud answers: The baraita means that one enters it in a chest, a box, or a cabinet. In this case he remains pure, as he did not come into contact with the ground itself.

דתניא: הנכנס לארץ העמים בשידה תיבה ומגדל ⁠– רבי מטמא, רבי יוסי ברבי יהודה מטהר. ואפילו רבי לא קא מטמא אלא בארץ העמים, דגזרו על גושה ועל אוירה, אבל סוריא, על גושה גזרו, על אוירה לא גזרו.

As it is taught in a baraita: With regard to one who enters the land of the nations, i.e., any territory outside of Eretz Yisrael, in a chest, a box, or a cabinet, R' Yehuda HaNasi deems him ritually impure, and R' Yosei, son of R' Yehuda, deems him pure. And even R' Yehuda HaNasi deems one who did not touch the ground itself impure only in the land of the nations, concerning which they decreed impurity upon both its clumps of soil and upon its air. However, with regard to Syria, everyone agrees that they decreed impurity upon its clumps of soil, but they did not decree impurity upon its air. Therefore, it is possible to enter Syria and remain in a state of ritual purity if one does not touch the ground itself.