Dear Rabbi, As I was looking at this week’s parasha, I saw the Artscroll drawing of the boundaries of Eretz Yisrael. According to the chumash, it seems that Eilat and other points south are outside biblical Eretz Yisrael. This brings up a few questions: 1) Are these areas considered outside of Israel for purposes of shmitah, Yom Tov sheni, etc? 2) If they are not, how does the conquering of these lands by the modern state of Israel constitute a valid halachic kinyan for these purposes? 3) If the modern state is capable of halachically adding land to Israel, how is it permitted to add lands outside the Torah mandate when much of biblical Israel is still under occupation by the PLO, Jordan, and Syria? 4) Once all of Israel is conquered, if Israel were to annex a distant island in the Pacific Ocean (or even build a moon base), would that land have the status of Eretz Yisrael with all the same pertaining halachos?
The questions you raise, especially regarding shmitta and other agricultural mitzvot, are dealt with extensively in halachic writings. A basic text is the article in the Talmudic Encyclopedia on Eretz Yisrael under the sub-heading: expanding its borders. There are differences of opinion as to how to view parts of the Land that were conquered by King Solomon (who reached Eilat=Etzion Gever) and how to see conquests in defensive wars since the founding of the State of Israel.The late Chief Rabbi HaRav Shlomo Goren wrote on this last subject in Torat HaMoadim p.614 where he concludes that conquest by itself is insufficient to define the conquered territory as the Land of Israel for the purpose of agricultural mitzvot. It is necessary for the sanhedrin to expressly sanctify the Land after its conquest. There is a concensus among the poskim that Eilat keeps one day of Yom Tov (see for example Shu"t Tzitz Eliezer III 23). After the Land of Israel we are commanded to conquer is in our hands, if we were to conquer and then to sanctify through the Bet Din other lands, these lands would have the halachic status of the Land of Israel regarding the agricultural commandments..