It is true that G-d promised the Land of Israel to the seed of Abraham, Isaac and Jacob, and this promise will be fulfilled again someday, when the messiah comes. However, Scripture makes it clear that until the coming of the messiah, the Jews will be in exile in various countries, and it will be only the messiah who gathers them in and reestablishes the Jewish kingdom. Here is a partial list of Scriptural texts proving that G-d, via His emissary the messiah, will be the one gathering us in: Isaiah 11:12, 27:12, 40:9, 41:14, 43:5-6, 52:12, 54:7, 56:8, Jeremiah 16:15, 23:3, 30:10, 31:9, 33:7, Ezekiel 11:17, 20:34, 28:25, 34:13, 37:21, 36:24. Hosea 1:7, Micah 2:12, Zachariah 4:6, 8:7, Psalms 53:7, 106:47.

In addition, the Talmud warns Jews with an oath not to force the end of exile, not to make war with the nations of the world, and not to ascend en masse to the Holy Land until the messiah comes.

The reasoning behind this is that a covenant is a two-way street. The Jews were not promised the land for no reason other than their genetic makeup. They have to keep the Torah to retain their rights to the land. Moreover, even a gentile can join the Jewish people and will have a right to the land. So we see that it is not primarily the race of the Jews that G-d is interested in; it is their beliefs and practices. As long as they kept the Torah, they were allowed to stay in the Holy Land, but when they violated it they were sent into exile. This is the exile we are still in today. When we repent, G-d will send us the messiah and bring us back to our land.