Over shabbat we discussed how by the year 2020 more Jews will be living in Israel than in the rest of the world combined, and someone brought up that many halachot would change, like that Shmitta becomes d‘oraita. What other mitzvot become d‘oraita and do some halachot change entirely? What is the reason for this change?
Moadim L'Simcha! Yes, thank God, according to the world-class demographer Prof. Sergio Della-Pergola of the Hebrew University, within 2 years, the majority of the Jews in the world will be living in Israel for the first time in about 2,700 years since the exile of the 10 Tribes (thanks to Aliya, the relatively high birthrate of Jews in Israel, and the low birthrate of Jews abroad, not to mention the unfortunate constant assimilation and “evaporation” of western Jewry). Although he doesn’t use the halachic definition of “Jewish” (i.e. going by one’s mother), regarding halachic Jews, we may already be there today!! Regardless of the difficulty in verifying the identity of the world’s halachic Jews, you are correct that we rabbis must definitely start working these questions out, and quickly! In short, according to the Rambam, the major and most accepted authority on the agricultural mitzvot, Shmitta will continue to be m’drabanan (until all 12 tribes return to live in their Biblical areas), but Trumot and Ma’asrot will soon be automatically upgraded to m’doraita (a Torah commandment). This is the understanding of the Chazon Ish and R. Isser Zalman Meltzer, whereas R. Chaim Soloveichik holds that the central Beit Din will have to officially declare “re-hallowfication” of the Land regarding these mitzvot, and it isn’t “automatic”. Regarding the status of mitzvat Challah, some hold that it also will automatically return to being d’oraita, but the Chazon Ish opines that Challa needs a king and prophet to return to her previous status. The reason is that the holiness of Eretz Yisrael is eternal and unconditional, but realizing this potential for such things like the aforementioned agricultural mitzvot, is achieved by the return of her loving husband, the People of Israel. Like in a good marriage, each spouse brings out the best in the other! So similarly, the Jewish nation only can achieve prophecy in the Land of Israel or for her sake (e.g. Moshe spoke to God in egypt to bring the Jews to Israel). Until the leading poskim decide on these big questions, I can just thank Hashem for living in this historic period, and wish Mazal Tov to all of the olim who are personally raising the level of holiness in Eretz Yisrael and her mitzvot!