Q. Were all the twelve Apostles Jews?
A. We have no good reason from Scripture or Tradition to think otherwise. Some of the Apostles had Greek names, but this was not uncommon among Jewish people in the eastern Mediterranean region of that time, given that Hellenistic culture dominated that part of the world.
In addition, the Apostles all worshipped in the Jewish temple with Jesus (presumably in the inner courts where Gentiles weren’t allowed), and they celebrated