This is a conceptual, Halachic, moral and current question. A number of “historic accidents” have brought people to abandon their Jewish roots. Sometimes this took place of their own free will but most of them had to act this way unwillingly, beginning with the Inquisition, through anti-Semitism, Communism and the Holocaust, all of which attempted to displace the Jews from their Judaism and from their brethren. However, in spite of everything, Israel is not alone, and God, who appears as the Angel of History, brings our brethren back home, back to their family.
Why bring the lost sons back to the Jewish people? Don’t we have enough troubles of our own? Why should we deal with people who aren’t Halachically Jewish?
In some cases, their Jewish origin can be proven though the existence of documents or objects that were handed through the generations in the family. Another way to research their roots is through finding the source of the family name. The problem is that these are not final proofs for a number of reasons: Firstly, because of the fact that any family name was the name of a Jew does not prove that it was only a Jewish name. In addition to this, even if it was a Jewish family name, without a genealogy that can cover several generations, one cannot say with certainty anything about a family’s Jewish heritage. But there is a third method: In many cases, the traditions that were passed down through the generations have produced in a person clear and incontestable belonging. Sometimes, this very feeling of belonging becomes the strongest drive for returning to the Jewish people.
Our modern arbiters of Halachah, such as Rabbi Tzvi Hirsch Kalischer, Rabbi Benzion Uzziel, expressed their opinion on this important topic for our generation. The Halachic response is clear and simple: A person’s religion is according to his mother. If the mother is not Jewish, the son is not Jewish. Nobody argues on this point. Anyway, what is to be our attitude to such an offspring? Is he like the other nations? Does he have a unique status? Is it a Mitzvah to bring him closer to Judaism or to distance him?
In general, the return process includes several preparatory steps. On the one hand there is an intellectual preparation that includes, in the main, studying. In order to become part of the Jewish people, it is very important to reclaim the lost memory, to know its history, customs and thought. Furthermore, it is very important that this knowledge break through the barrier of theory, become a way of life, that the traditions and customs become part of everyone’s daily life. These two aspects can be completed by self-learning, through reading and studying or with the assistance of a teacher, instructor or rabbi. On the other hand, there is an additional requirement of integrating into communal life. Judaism was always characterized by its social life. Therefore, there is the highest importance for meeting within a Jewish context. In this aspect, the best decision is to approach the closest local community.