Source: Far More than 13 Million – Judaism – Arutz Sheva

“Rov Yisrael” and the Obligation of MitzvothDependent on the Land
Presently, we are obligated to fulfill the mitzvot of Shmitta (the Sabbatical year), challah (separating a section of dough from kneading and giving it to a kohen), terumot and ma’asrot (tithes) only derabanan (by rabbinic authority). When ‘rov Yisrael‘ (literally, ‘the majority of Jews’) live in the Land of Israel, as termed by our Sages “rov yoshvei’ha aley’ha” (“the majority of its inhabitants dwell in it”), we will have fulfilled the conditions for being obligated in the mitzvot of challah and tithes from the Torah. And when the Jewish nation lives in the Land of Israel as required, every tribe in its place, we will also merit observing the mitzvah of Shmitta and Yovel (the Jubilee year) from the Torah.