Your letter made me very sad and my heart goes out to you at this most difficult of times. Not knowing your child and his or her personality it is almost impossible for me to say with any certainty what might be the approach for him. However, in my experience I have seen over and over again that when a child is sees and feels the enormous love that a parent has for them the greater the chances are that they will return to their true ideals and beliefs. That does not mean, God forbid, that you should let him think that you condone their relationship – you should make it perfectly clear, albeit in a gentle way, that you are completely broken by his actions.
I am sending you a series of arguments and quotes for your perusal and I hope and pray that you will be able to find something to help you.
The practice of not "intermarrying" is in fact one of the oldest features of Judaism. It dates back to Abraham telling Eliezer, his servant, not to find a wife for his son from the Canaanites. It continues with Isaac's command to his son Jacob not to marry the "daughters of the land." The practice is mentioned in the Bible as a legal prohibition, and is also part of the covenant that Ezra the scribe had the Jews make when they rebuilt the Temple after the Babylonian Exile.
In all the above cases the underlying idea of the prohibition seems to be ideological. As Jews, we have a unique identity that is connected to our purpose in the world. We are the "chosen people." We were chosen to propagate the ethical monotheism of Judaism. In the words of Leo Tolstoy: "The Jew is that sacred being who has brought down from heaven the everlasting fire, and has illumined with it the entire world. He is the religious source, spring, and fountain out of which all the rest of the peoples have drawn their beliefs and their religious. The Jew is the pioneer of liberty. The Jew is the pioneer of civilization. The Jew is the emblem of eternity."
We were chosen as a permanent protest group against idolatry and immorality. Intermarriage is therefore antithetical to the Jewish purpose and to the Jewish identity. Can we prove that we are chosen? Do we have evidence? Yes. In a brief look at history we can see the antiquity, survival and impact of the Jewish people as unique and remarkable. I don't think that I can put it better than Mark Twain, in his famous description of Jewish history, "An Essay Concerning the Jews": "If the statistics are right, the Jews constitute but one percent of the human race. It suggests a nebulous dim puff of star dust lost in the blaze of the Milky Way. Properly the Jew ought hardly to be heard of; but he is heard of, has always been heard of. He is as prominent on the planet as any other people, and his commercial importance is extravagantly out of proportion to the smallness of his bulk. His contributions to the world's list of great names in literature, science, art, music, finance, medicine, and abstruse learning are also away out of proportion to the weakness of his numbers. He has made a marvelous fight in the world, in all the ages; and has done it with his hands tied behind him. He could be vain of himself, and be excused for it. The Egyptian, the Babylonian, and the Persian rose, filled the planet with sound and splendor, then faded to dream-stuff and passed away; the Greek and the Roman followed, and made a vast noise, and they are gone; other peoples have sprung up and held their torch high for a time, but it burned out, and they sit in twilight now, or have vanished. The Jew saw them all, and is now what he always was, exhibiting no decadence, no infirmities of age, no weakening of his parts, no slowing of his energies, no dulling of his alert and aggressive mind. All things are mortal but the Jew; all other natio
