Genealogy /
Surname Łos from Białystok [28]
But it is ! The member of the tribe have to have "blood" of the tribe without a doubt(thats why mother is more important). It means that "blood" of the tribe is sacred and have special role as a vessel bonding past and present generations together as a one sacred and special entity.
Sacred and special role for sure. But if it were only based on blood then converts would not be accepted. Yet a convert to Judaism is considered equal, legally and spiritually, to a born Jew. I'll try to explain it this way:
In ancient times, G-d made a covenant with Jacob and all of his his descendants. The agreement was we would have to follow G-d's law and worship Him alone and in turn, G-d would settle us in the Land of Canaan and give us his protection and blessings. The purpose apparently was for us to be a holy nation that would serve as an example (or as an experiment?) that would eventually be followed by the rest of the world. This agreement is unending and unlaterable as long as there are descendants of Jacob (Israel). Besides for blood descendants, anyone from any nation who identifies with this mission and accepts the burden of keeping the laws of the Torah can join the "holy people".
Now you can say this is terribly chauvinist, but this story is an integral part of western civilization, thanks to the christian religion, which spread this story to the western world. While christians tend to emphasize the failures of the Jews to live up to their special mission, no christian can deny that we were originally chosen to fulfil G-d's mission. We haven't succeeded yet, but we're still trying. And anyone born of a Jewish mother can feel privileged to be part of this, but should also feel awe at the difficulty and seriousness of trying to live life as a Jew should. Anyone not born of a Jewish mother is also welcome to join, as long as they are aware that undertaking to serve G-d as a Jew is not something to be taken lightly. For anyone who sincerely wants this, I say welcome to the gene pool.