We also find in Bava Kamma (80b):
“When one purchases a house in Eretz Yisrael, we may write the deed of purchase even on the Sabbath. May we actually write it on the Sabbath? Rather… one may tell a non-Jew to write it. And even though telling a non-Jew to perform work forbidden on the Sabbath is itself rabbinically forbidden, the Rabbis did not apply decrees where settling Eretz Yisrael was at stake.”
Rashi comments (Gittin 8b: “I.e., expelling the nations and settling Jews there.” Rambam (Hilchot Shabbat 6:11) ruled this way, too, as well as Shulchan Aruch, Orach Chaim 306:11. If the mitzvah of living in Eretz Yisrael did not apply today, or even if it were only rabbinic in force, how would we dare permit this rabbinically forbidden act on the Sabbath? After all, Tosafot wrote (Bava Kamma 80b: “Specifically for this mitzvah of living in Eretz Yisrael, but for another mitzvah, telling a non-Jew to violate a Torah prohibition is not permitted.”
Our Sages further said (Jerusalem Talmud, Sotah 8:4) regarding one who returns from the battlefield because he has built a new house and not lived in it: “I might think that someone who has built a new house outside the Land should have to return from the front. It therefore says, ‘And has not begun to live in it’ (Deut. 20:5). The verse refers to one for whom living in it is a mitzvah (in the Land of Israel), and excludes all others (living outside).
“P’nei Moshe” comments (Ibid.), “One for whom it is a mitzvah: In Eretz Yisrael, due to the mitzvah of living in the Land. This excludes outside the Land, where there is no mitzvah to live there.”
Ramban further wrote (Sefer HaMitzvot, Positive Precepts Not Mentioned by Rambam, Mitzvah 4):
“We were commanded to occupy the land God gave our ancestors, Abraham, Isaac and Jacob. We must not abandon it to any other nation, or leave it desolate. God said, ‘Clear out the Land and live in it, since it is to you that I am giving the Land to occupy’ (Num. 33:53-54). Proof that this is a mitzvah comes from God’s saying in the spy episode, ‘Head north and occupy it, as the Lord God of your fathers has told you. Do not be afraid and do not be concerned’ (Deut. 1:21). Furthermore it says, ‘At Kadesh Barnea, the Lord sent you forth and said, Head north and occupy the land that I have given you’ (Deut. 9:23). And regarding the Spies’ not wishing to go up to the Land, it says, ‘You rebelled against the Lord’ (Deut. 1:26,43; 9:23), and, ‘You would not listen’ (Deut. 1:43). God’s word to Israel had been a command rather than a promise.”
So effusively did our Sages speak of living in Eretz Yisrael that the Talmud states (Ketuvot 110b), “Whoever leaves Eretz Yisrael and dwells outside of it should be viewed as an idolater, as it says, ‘They have driven me out this day that I should not cleave unto the Lord’s inheritance, saying, ‘Go serve other gods’” (I Sam. 26:19).
This, and other such expressions in this regard, find their source in our having been commanded to occupy the Land and to dwell in it. It is, thus, a positive precept for all time, and every single Jew is obligated in this, even during the exile, as the Talmud is known to state in many places.
It is, thus, clear that God not only gave the Jewish People a special Land, but also decreed that they must live in it. Living in the Land is not merely a right, but a duty that cannot be forgone. It is a mitzvah, a Divine decree, that we must live in Eretz Yisrael under God’s dominion, sanctifying His name, in order to create a holy state and society which clings to mitzvot completely and properly, uninfluenced by the alien, false culture of the nations.
At the same time, it is an unforgivable, loathsome sin to refuse to live in Eretz Yisrael, and to prefer the depravity of the exile and foreign rule. It is a Chillul Hashem, and Israel as thus exposed to the influence of the nations and their abominations.