Why is Jewish Identity Determined by the Mother?

Greetings,

The source for determining that the Jewish identity of children is based on the mother and not the father is from what is written in the Torah (Deuteronomy 7:3-4) "And you shall not intermarry with them; you shall not give your daughter to his son or take his daughter for your son, for he will turn your son away from following Me, and he will serve other gods."

In this verse, there are two ways of marriage: a daughter of Israel with a non-Jew and a son of Israel with a non-Jewish woman. However, the verse concludes with "for he will turn your son away," which only refers to the way in which the non-Jew marries a daughter of Israel. Apparently, the verse should also have addressed the way in which a son of Israel marries a non-Jewish woman and said, "for you will turn your son away."

Rather, the Gemara in Tractate Kidushin (68b, and Rashi there) teaches that a son born from a Jewish mother is called your son, while a son born from a non-Jewish woman is not called your son but her son. Therefore, the Torah only states, "for he will turn your son away," which is in the context of a daughter of Israel marrying a non-Jew, since her son is Jewish, and his non-Jewish father will turn him to serve other gods. However, the Torah does not say, "for you will turn your son away," referring to the situation where a non-Jewish woman marries a Jew, since the son born to them is not considered your son because he is non-Jewish.

With blessings,

Hillel Meirs