Hashem's command that Avram, the first Jew, leave his birthplace and undertake the long and dangerous journey to an unnamed land is the Torah's first reference to Eretz Yisrael. This command could also be viewed as the beginning of Jewish history, as it is the event which demonstrates in a most tangible way the distinction which Hashem put into place between Avram and his descendants and the rest of the world. At first glance, this seems to be very logical-Hashem, noting Avram's unique devotion, grants his descendants a unique status as a nation who will relate to Him in an enhanced way. What better way to graphically illustrate this change than by transplanting Avram from his father's idolatrous home to Eretz Yisrael, a new land of holiness?
If we consider the specific nature of Avram's (and similarly our) mission in the world, we may note a disturbing incongruity: Avram's trademark is "Kiruv," bringing others closer to G-d, and yet Hashem removes him from among the masses and sends him to lay the groundwork for a new nation where his descendants would live apart from all other peoples. Does this not greatly weaken the ability of the Avram and the Jews to serve as an אור לגוים, a beacon of righteousness for the rest of the world? Would it not be more correct for the Jews to be dispersed throughout the world, as we still are to an extent today, so that their impact could be maximized?
Apparently, we have misinterpreted the distinction of which Eretz Yisrael is symbolic, as well as the method of Kiruv which Hashem endorses. Through a more comprehensive understanding of both of these, our question can be resolved. Eretz Yisrael, the most physical manifestation of the distinct identity of the Jews as separate from all other peoples, is intended to be the home of a flourishing Jewish society, exemplary in its morality. This society must maintain a wary distance from outside influences in order to develop properly. Neither an individual nor a nation can serve as a proper role model if it interacts predominantly with those whom it wishes to influence. The separation is thus put into place to allow the Jews to grow into the most ethical and G-d fearing nation they can become, and thus into the most effective אור לגוים.
Now we can also understand Hashem's ideal system of Kiruv. Hashem does not want the Jews to engage in missionary activity, to convert the entire population of the world to Judaism. He is not interested in having us directly preach our beliefs to others. Rather, He wants us to achieve the spiritual heights which we are capable of, in our own Jewish society. The most effective testimony to the greatness of Hashem is a prosperous and smoothly functioning nation with all the usual institutions (a ruler, an army, courts, etc.) which is strictly dedicated to serving Him. Hashem wants the nations of the world to perceive the causal relationship between serving Hashem and becoming an ethical and successful person. It is a nation that serves as an example in this manner that is called a "ממלכח כהנים וגוי קדוש," spiritual leaders of the world who also maintain a certain separateness.
This, essentially, is the national mission of the Jews. We must strive to bring awareness of G-d into the world by administrating a functional nation based on the specifications of the Torah. While the modern State of Israel does not at present fulfill this function fully, it certainly is a step in the right direction. In our own time, we are witnessing the final return to the land which Hashem promised to Avram; we would be remiss to ignore this phenomenon. Rather, we must do all that we can to support the development of Eretz Yisrael as a center for Avodas Hashem, and an embassy of Shamayim on Earth. Through our enthusiastic involvement in this project, we can hopefully bring the day when the prophecy, "ומלאה הארץ דעה את ה` כמים לים מכסים" will be fulfilled.