Why is Judaism passed down through the mother? I understand in olden times it was easy to know who your mother was and there was no way of proving fatherhood. But these days we have DNA testing, so why can't someone be Jewish even if only their father is Jewish?
Jewishness is not in our DNA. It is in our soul. The reason it is passed down through the maternal line is not just because it is easier to identify who your mother is. It is because the soul identity is more directly shaped by the mother than the father.
Jewishness is not in our DNA From a purely physical perspective, a child is more directly connected to their mother. The father's contribution to the production of a child is instantaneous and remote. The mother, on the other hand, gives her very self to the child . The child is conceived inside the mother, develops inside the mother, is sustained and nourished by the mother, and is born from the mother.
This is not to say that a father and child are not intimately attached. Of course they are. But as deep and essential as the bond between father and child may be, the child's actual body was never a part of her father's body. But she was a part of her mother. Every child begins as an extension of their mother's body.
This is a simple fact. It doesn't mean she will be closer to her mother, or more similar to her mother, or follow her mother's ways. We are not discussing the emotional bond between parent and child, but rather the natural physical bond. There is a more direct physical link between mother and child, because a child starts off as a part of her mother.
The body and its workings are a mirror image of the workings of the soul. The physical world is a parallel of the spiritual world. And so, the direct physical link between mother and child is a reflection of a soul link between them. While the father's soul contributes to the identity of the child's soul, it is the mother's soul that actually defines it. If the mother has a Jewish soul, the child does too.
If the mother is not Jewish but the father is, his Jewish soul will not be extended to the child. There may be a spark of Jewishness there, but if it was not gestated in a Jewish mother, the child will have to go through conversion for their Jewishness to be activated.
Jewishness is passed down by the mother because being Jewish is a spiritual identity, it defines our very being. And our very being we get from our mother, both in body and in soul.