Last Shabbat, we read parashat Hayei Sarah, in which Abraham commands his servant Eliezer to go to the land of his birth, Aram Naharayim, to find a wife for his son Isaac. (Aram Naharayim is the land between the two great rivers – the Euphrates and Tigris – later called Mesopotamia, today on the Turkish-Syrian border.Abraham warns Eliezer and makes him swear not to bring Isaac a wife from among the women of Canaan, but, rather, only from among his family in his native land. And so, Eliezer arrives in Haran, meets Abraham’s relatives, and brings Rebekah to Canaan to marry Isaac: “…and he took Rebekah, and she became his wife, and he loved her” (Genesis 24:67).Jacob tricks Isaac into giving him his older brother Esau’s blessings. Esau becomes infuriated and intends to take revenge and kill Jacob. Rebekah, aware of Esau’s scheme, warns Jacob and tells him to escape to her native land – Haran in Aram Naharayim – where her older brother, Laban, resides. Isaac, who is unaware of Esau’s plans, is told a different story:“And Rebekah said to Isaac, “I am disgusted with my life because of the daughters of Heth. If Jacob takes a wife of the daughters of Heth like these, from the daughters of the land, of what use is life to me?” (Genesis 27:46).In response, Isaac instructs Jacob: “You shall not take a wife of the daughters of Canaan. Arise, go to Padan Aram... and take yourself from there a wife of the daughters of Laban, your mother’s brother.”And then Isaac adds: “And may the Almighty God bless you.... And may He give you the blessing of Abraham, to you and to your seed with you....” (ibid. 28:1-4).Isaac teaches us that the blessing of Abraham is contingent upon the purity of the marriage. If one is stringent about a kosher marriage, one merits the blessing of Abraham.Indeed, the Jewish nation throughout the generations has viewed this as a core principle: intermarriage is seen as a very serious transgression. Jews only marrying Jews has been crucial to the survival of the Jewish nation.Amazingly, despite the nation being dispersed all around the world for thousands of years, we have maintained our faith and lifestyle, allowing us to survive and return to our homeland. A survey of other nations from ancient times that have not survived, and a comparison of them with the Jewish people, reveal the inescapable insight that a nation that did not preserve marriage within the nation and intermarried with other nations was not able to preserve its national culture or traditional lifestyle.There are those who see the prohibition to marry a non-Jew as racist. This mistake stems from a misunderstanding. Judaism does not disqualify any person or any race. Anyone, of any race, can join the Jewish people – if they take upon themselves the principles of Jewish faith and the commandments that stem from it. No one has ever been disqualified from joining the Jewish nation due to the color of his skin or the land of his origin.Furthermore, research into the ideological foundation of the entire equal-rights concept will not find its source in classic Greek thought or anywhere else that might have influenced Western thought. The equal-rights concept originated in Judaism, which sees every person – irrespective of gender, race or religion – as someone created “in God’s image.”However, Judaism has also ingrained in us the important understanding that there is no way to preserve our principles of faith and lifestyle while assimilating in a society that stands for different principles. This separatism is essential in order to preserve Judaism, while pride and arrogance are disgraceful traits, and racism is a crime intolerable to Judaism. The writer is rabbi of the Western Wall and holy sites.In this week’s Torah portion, Toldot, we deal with the same topic.