Dear Rebecca,

I know that when we were growing up, I wasn’t such a good sister to you. Most days, I caused you to cry in one way or another. You tried to spend time with me, and instead of being a friend to you, I would yell, “Leave me alone!” Looking back, I realize that it must have been very painful for you to be despised with such passion by one of the people you most looked up to in the whole world, your older sister.

I would still like to ask for your forgivenessI am not a person who has so many big regrets in life. But I regret with all my heart the way I treated you for so many years. The way I acted when we were younger is, I believe, the worst thing I have ever done.

Both of us have been grownups for many years now. Today, I am married with several children, and you are already a professor. It is 20 years too late. But I would still like to ask for your forgiveness. I wish there was a way to turn back the clock and redo what was.

In recent years, our blossoming friendship has been a huge blessing in my life. It’s true that we live on opposite sides of the country, and neither of us is the best correspondent. But when we are together, I feel happy in your company and hope that you feel happy in mine as well. I hope that our newfound relationship has made up, at least in part, for the way I treated you.

In light of our past difficulties, it is awkward for me to get to the point of this letter. I so do not want to criticize you, as I did far too often when we were children. I hope that you will understand that the following paragraphs come from the opposite pole of my heart altogether. The following words, as painful as they might be for you to hear, are coming from a place of love. I wish that I did not have to say anything, but I feel that I have no choice.

I would like to talk with you about Mike.

You and Mike, in most ways, appear to be a match made in Heaven. You are both brilliant, yet so effortlessly humble that people who meet you outside of the workplace would never have any idea. You are both young and rising stars at your respective universities, yet impeccably kind-hearted and gentle. You are both so happy together, yet always able as a couple to make others comfortable in your presence in your own quiet and understated way.

I think you know that I like Mike a great deal. I really do. I think he is a wonderful person. I would be thrilled to have him as a brother-in-law . . . except for one thing.

Your very existence is a testament to their sacrificesRebecca, I know that being a Jew is important to you. I know that you travel across the country every year to attend the family seder on Passover. I know that when you were younger, your beloved Jewish summer camp pushed you to develop a sincere and profound connection with the Jewish people. I know that you were a leader of the Jewish community at your college, organizing events and getting people excited about being Jewish, even when most of your fellow Jewish students were getting excited about everything but.

I was recently thinking about the fact that the only reason either of us is Jewish today is thanks to the courage and determination of our ancestors who, for 3,700 years, withstood persecution, abuse and threats of death so that one day they would have a Jewish great-great-great-granddaughter named Rebecca. Your very existence is a testament to their sacrifices, to their devotion to the Torah, to their intense prayers that their descendants would stay loyal to Judaism.

You, Rebecca, are the fulfillment of all their dreams. A Jewish descendant! A Jewish descendant with a strong Jewish identity, no less! You, Rebecca, are the link in the chain between your ancestors and your descendants. You are the link in the chain between our family’s past and our family’s future.

According to statistics, if you marry Mike, there is only a one in 10 chance that your children will even identify as Jews. If you marry Mike, there is almost no chance that your grandchildren will be Jewish.

If you marry Mike, the dreams of thousands of our ancestors will die on your wedding day.

Over the past few years, you have been so busy with your studies, and now your career, that Judaism has been relegated more and more to the margins of your life. At this stage in your life, it might seem that you don’t have the time or feel the need to turn your positive feelings towards Judaism into actual observance on an ongoing basis.

But when you marry and become a mother, with G‑d’s help, I think that once again, you will want Judaism to play a central role in your life and the life of your family. You will want to raise your children in a Jewish home. You will want to raise your children, as Mom and Dad raised you, with Hebrew school and Jewish camp and the holidays.

I want to cry tears of happiness at your chuppahTens of thousands of Jews have married non-Jews with similar worthy intentions, only to realize when it is already too late that raising a Jewish family with a non-Jewish partner is a near impossibility.

You are my sister. I want to dance at your wedding. I want my daughters to be your flower girls. I want to cry tears of happiness at your chuppah.

I love you. I admire and am very fond of Mike. But if you marry him, as difficult as it will be for me as well as for you, I will not be able to attend your wedding. I could not attend your wedding because, as Jews, what would happen on your wedding day would not be a happy event. It would be a tragedy of historic proportions.

I wish that this was not a letter that I had to write. I wish that I could just keep on smiling and acting as though everything is all right, like everybody else in our family. But I feel that, as painful as this is, because I care about you as much as I do, I must tell you the truth.

With love,

Your sister