From God's very first command to the very first Jew - "Get thee forth from thy country, thy birthplace, thy father's house, to the land which I shall show thee" (Genesis 12:1) - Zionism has been a fundamental tenet of Judaism. And indeed, the major transgression of the Book of Numbers was the refusal of the freed Hebrew slaves to conquer and settle the Land. Our portion of Mattot, coming as it does at the conclusion of Numbers and describing the willingness of the next generation - the children of those who left Egypt but died in the desert - to fight for the Promised Land even uses the biblical term "halutz" (pioneer, advance guard) for the first time. But is there a proper Zionist motivation and an improper Zionist motivation? For what reason should Jews desire to live in Israel in order for their aliya to be successful? And, given the many successful Diaspora communities such as Teaneck, New Jersey; West Side, Manhattan; Dallas, Texas; Hendon, London, how can the Talmud declare that there is no authentic Jewish community (kahal) outside the Land (B.T. Horayot 3a)? The answer to these questions is found in a fascinating dialogue between Moses and tribal representatives of Gad and Reuben in this week's biblical reading. Let us begin with Gad and Reuben. They apparently want to settle trans-Jordan immediately, and so make their request before Moses (Numbers 32:1-5). The prophet quite correctly chides them, apparently throwing out the challenge: "Why should your brothers go out [to the other side of the Jordan] and fight while you stay here? Why are you trying to discourage the Israelites from crossing over to the land that God has given them?" (32:6). So they agree to arm themselves and go out as an advance guard (halutzim) "before the other Israelites," settling the eastern bank of the Jordan River only after their brethren have settled the western bank. However, the dialogue continues for another 19 verses, with each side seemingly repeating their positions over and over. Why the repetition? This dialogue opens with the words: "The descendants of Reuben and Gad had an extremely large number of animals, and saw that the Jazer and Gilead areas were good for livestock. The descendants of Gad and Reuben therefore came and presented the following petitionâ€¦." (32:1, 2). Clearly, their motive for settling the Land was materialistic; it would be good grazing area for their cattle. Indeed, they even mention their livestock to Moses first, and only later their children: "We will bring enclosures for our sheep here and cities for our children" (32:6). Moreover, they refer twice to their willingness to fight "before the children of Israel," whereas Moses stresses no fewer than six times that they must be an advance guard (halutzim) "before the Lord" (32:20). And so the dialogue can only conclude when the Gadites and Reubenites internalize Moses's message: "Our children, wives, property and livestock will remain here in the cities of Gilead. Meanwhile, our special advance forces (halutz) will cross over before God to wage battle" (32:26, 27). In a word, Zionism for materialistic reasons - or on behalf of the people of Israel alone - is not sufficient; Zionism must be for the sake of the future - Jewish continuity - and as part of God's divine commission that we teach justice, compassion and peace to the world. From this perspective, I also understand the talmudic statement (B.T. Horayot 3a) about kahal, community, only existing in Israel. Israel is the land wherein God promised Abraham "through you shall be blessed the families of the earth" (Genesis 12:3); Israel is the land wherein God entered into His "covenant between the pieces" with Abraham, guaranteeing him an eternal progeny; Israel is the land wherein God charged Abraham with instructing all following generations to act with righteousness and justice (Gen. 18); Israel is the land where Abraham and Sarah, Isaac and Rebekah, Jacob and Leah are buried. Israel is the land where our prophets walked and saw their visions of world peace - a time when all nations will beat their swords into plowshares and their spears into pruning hooks. And Israel is the land where King Solomon built the Temple, dedicating it as a place for gentiles as well as Jews, and from whence the entire world will recognize a God of love and morality, peace and redemption. Israel is the land of Jewish continuity, the headquarters of the Jewish mission. The verse which the Talmud cites is from I Kings, where Solomon - in celebrating the dedication of the Temple - calls the Jews of Israel "Kehal Yisrael." From this perspective, the very stones and air of Israel pulsate with Jewish vision, the Jewish goal of world peace. Indeed, we settle the Land - most importantly - for our children and the God who desires world peace. The writer is the founder and chancellor of Ohr Torah Stone Colleges and Graduate Programs, and chief rabbi of Efrat.