Matrilineal Descent

Rabbeinu Bechaye has an interesting take on the episode of the blasphemer. He writes that the Torah made a point of telling us that he was בן אשה ישראלית, that he was the son of an Israelite woman. He was also בן איש מצרי, the son of an Egyptian man.

Rabbeinu Bechaye saw this as a further proof that we follow the mother to determine if someone is Jewish or not.

The gripe of this man was that he wanted to pitch his tent with the Tribe of Dan as his mother was from Dan. Other members of Dan forbade him from being there. This enraged him and caused him to curse G-d, which led to his being put to death.

They really needed to settle the issue of connecting a tribe to a non-Jewish father. The blasphemer should have waited for the matter to be solved. But, incidentally, we learned about matrilineal descent.