If the Jew is a woman, you get a black Jew. If the mother isn't Jewish, then the child isn't either.
a black Jew
Jebus
Jesus
a Jew.
Jesus Christ
kilu mamo
Judaism is a religion. Black is a race. You can be one, both, or neither.
The most famous Jew to live in an Arab land was Maimonides.
no christian
probably Rudolf Vrba.
Black Jews observe Shabbat no differently than any other Jew.